Human romantic and sexual relationships and behaviors have been studied from a wide variety of disciplinary perspectives, including evolutionary and life history approaches (Fisher 1992; Gray and Garcia 2013; Low 2000; Symons 1979; Townsend 1998). Within the framework of evolved mating psychology, an extraordinary amount of research has focused on the underpinnings of reactions to infidelity. Sparked by a now classic set of studies conducted by Buss et al. (1992), this research has generally found that in a forced choice paradigm, women were more likely to be most distressed by emotional infidelity whereas men were more likely to be most distressed by sexual infidelity. This research has tended to examine sex differences in jealousy and responses to infidelity as sex-specific psychological adaptations, which are putatively due to human females’ relatively higher obligatory parental investment and lower potential reproductive rate, and human males’ relatively lower obligatory parental investment and high potential reproductive rate (see Buss 2000). Although most of these studies have focused on Western industrialized populations, this pattern of findings has also been shown in a sample from a non-industrialized settings (Scelza 2014), further lending support for the existence of an evolutionary basis. For practical purposes, emotional and sexual infidelities have been operationally defined in various ways so that this line of research could address specific questions related to the psychology of infidelity. For example, previous research has asked participants how upset or distressed they would be if they imagined their partner “…having sexual intercourse with [a] person, but you are certain that they will not form a deep emotional attachment” or “… imagining your partner forming a deep emotional attachment to that person, but you are certain that they will not have sexual intercourse” (Buss et al. 1999, p. 132). Although these definitions, and other similar versions used by other researchers, most likely target the broad idea of sexual and emotional infidelity, the extent to which the definitions used for these constructs accurately reflect participants’ conceptualizations of infidelity has received less attention, and is the focus of the current research.

Previous research has been conducted under the assumption that people, particularly those sampled in contemporary Westernized settings, do in fact distinguish between two discrete types of infidelity in their relationships. But, what exactly is emotional infidelity? And what exactly is sexual infidelity? More specifically, how do real people understand and conceptualize these seemingly discrete concepts? The current research seeks to understand how people define these concepts in their own lives. We also seek to explore how many distinct definitions of each type of infidelity are generated by men and women. Further, we address how these definitions explicate what people see as prototypically different in sexual infidelity and emotional infidelity as different classes of infidelity. Using a mixed methodology, which includes some participants generating open-ended definitions of each kind of infidelity and other participants rating the degree to which these definitions are prototypical of the emotional and sexual infidelity categories, we are able to document which naturally generated definitions of infidelity fit the prototypicality of specific categories to the minds of real people.

Research on Sex Differences in Reactions to Infidelity

A series of research studies have examined different reactions to sexual infidelity versus emotional infidelity, with a particular emphasis on sex differences (e.g., Abraham et al. 2001; Buss and Haselton 2005; Buss et al. 1992; Shackelford et al. 2002). Researchers disagree as to whether sex-specific responses to (potential) infidelity constitute evolved adaptations (e.g., Buss et al. 1992) or more culturally determined and highly variable responses (e.g., Harris 2003; Harris and Christenfeld 1996). For instance, Harris (2003) review of the infidelity literature found a great degree of variability in men’s responses to hypothetical infidelity–with many samples showing more men than women indicating greater distress from emotional infidelity than sexual infidelity. However, Sagarin (2003) has argued that Harris (2003) results may be largely due to (among other factors) reviewing some self-report studies that did not examine reactions to emotional infidelity, and some that measured participants’ focus on sexual and emotional infidelity rather than ensuing jealousy. In any case, there has been much discussion in the literature as to the ultimate factors that surround male versus female reactions to infidelity.

Long-term sociosexual pair-bonds represent the most common and culturally consistent context for human sexual activity to occur, and as such pair-bonds are naturally associated with a variety of neurophysiological, psychological, and socially scripted mechanisms that serve to maintain these relationships (Fisher 1992, 2004; Gray and Garcia 2013; Sternberg and Weis 2006). Yet, humans appear to have evolved a dual reproductive strategy, with both intense pair-bonds (in the form of life long or serial monogamy) and clandestine adultery (Fisher 1992, 2011). Cross-cultural data suggest that non-consensual sexual activity outside the pair-bond relationship (i.e., sexual infidelity) is a fairly universally understood betrayal of a pair-bond, with both men and women typically distraught by sexual infidelity (Buss et al. 1999; Jankowiak et al. 2002). Such findings suggest a sex-similar conceptualization, and reaction, to sexual infidelity. However, it is also important to note that there may be sociocultural dynamics which may permit or prevent one’s internal reaction from materializing, such as women not publically denouncing their husband’s infidelity for fear of retaliation (Jankowiak and Hardgrove 2007).

Emotional infidelity, however, is somewhat more vague and difficult to understand, as compared to sexual infidelity. Emotional infidelity is thus likely more susceptible to be influenced by other factors, including participant sex, local gender roles, and unique dyadic characteristics of a couple. Further, most research on this topic relies on participant ratings of definitions of emotional infidelity based on categories created by the researchers themselves, rather than actor generated conceptions. Thus, the problem of how people actually conceptualize emotional infidelity remains underexplored. To our knowledge, no comprehensive open-ended studies have yet been conducted to examine how adults define and interpret these constructs. This point is explicated by the fact that much of the classic literature in the field that summarizes these phenomena only speaks to researcher-defined, as opposed to participant-generated, ways to conceptualize infidelity (Abraham et al. 2001; Buss et al. 1992, 1999; Buss and Haselton 2005; Shackelford et al. 2002; Jankowiak et al. 2002). Yet, without such data, researchers are unable to understand the parameters of emotional infidelity and sexual infidelity in order to inform how adults conceptualize these constructs that are so often studied in psychological research.

Current Studies

The current article includes two studies with separate samples of participants. In Study 1, participants from three universities provided open-ended definitions of what they believe constitutes sexual infidelity and emotional infidelity as part of a larger study examining multiple facets of infidelity (for additional results see Kruger et al. 2015). As an extension of Study 1, Study 2 had a separate group of participants rate participant-generated definitions from one of the institutions for prototypicality (i.e., the extent that they agree that the definitions provided are prototypical of each type of infidelity). These results were analyzed by identifying and examining the definitions that had the highest mean ratings.

Study 1

Participants

Undergraduate students (N = 379; 71 % women, M age = 21, SD age = 5, age range: 18–77) recruited from two public Mid-Western USA universities and one public Northeastern USA university completed an anonymous online questionnaire. In terms of sexual orientation, 3 % of women and 8 % of men reported being equally or more attracted to the same sex. Data from one participant who self-identified as transgender was removed. Participants were asked to complete the surveys in locations where their responses would be private.

Materials and Procedure

Data for Study 1 were collected by a web-based questionnaire administered electronically via Qualtrics (www.qualtrics.com). In randomized order, participants were asked to answer the following questions: “How would you define sexual infidelity?” and “How would you define emotional infidelity?” Participants provided open-ended responses without word limits. Following the above questions, and again in randomized order, participants were asked: “Do you think that something could be emotional infidelity without being sexual infidelity?” and “Do you think that something could be sexual infidelity without being emotional infidelity?” Those participants who answered Definitely Yes, Probably Yes, or Maybe/Not Sure were asked the following: “Please give examples of emotional infidelity without sexual infidelity” and “Please give examples of sexual infidelity without emotional infidelity.” Those who answered “Probably No” or “Definitely No” skipped these questions.

Analyses

A team of five undergraduate coders reviewed and categorized the open-ended responses into themes. Each response was coded for whether or not it contained each specific theme. Coders initially worked independently, and then resolved discrepancies until agreements were unanimous. Initially, 7 % of the codings were discrepant; these were resolved by coder discussion and all coders agreed on the final coding. We examined the correspondence between themes expressed in definitions from the initial items with those from the “pure” items (i.e., sexual infidelity without emotional infidelity). We examined responses regarding the existence of “pure” sexual and emotional infidelity with a 2 (participant sex) x 2 (type of infidelity) ANOVA for mixed designs.

Results

The majority of women (88 %) and men (79 %) thought that emotional infidelity could occur without sexual infidelity, and that sexual infidelity could occur without emotional infidelity (71 and 54 %, respectively, see Table 1). A chi-square test revealed that the 54 % of men who reported that sexual infidelity could occur without emotional infidelity was not significantly above 50 %, Χ 2(1) = 0.73, p = .393. However, considering the responses as a continuous measure, male responses are significantly higher than neutral, t(110) = 4.29, p < .001. Thus, men tend to agree that sexual infidelity could occur without emotional infidelity.

Table 1 Percentage of participants that believe emotional infidelity and sexual infidelity can operate independently of one another
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Additionally, both women and men were more likely to think that there could be emotional infidelity without sexual infidelity than sexual infidelity without emotional infidelity, F(1377) = 48.68, p < .001. Women were more likely to think that there could be “pure” sexual infidelity and emotional infidelity (one kind without the other) than men, F(1377) = 17.27, p < .001. The interaction between participant sex and type of infidelity was not significant, F(1377) = 0.58, p = .811.

Content analysis of sexual infidelity definitions is presented in Table 2. In contrast to definitions in the initial question, definitions of sexual infidelity without emotional infidelity were more likely to mention lack of feelings or relationship intentions for a third party (52 vs. 0.3 % in the initial question), intoxication by alcohol or other drugs (8 vs. 0.3 % in the initial question), and paying for sex (5 vs. 0 % in the initial question).

Table 2 Percentage of responses coded for prevalent themes in response to the questions: “What is sexual infidelity?” and “What are some examples of sexual infidelity without emotional infidelity?”
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Content analysis of emotional infidelity definitions are presented in Table 3. In contrast to definitions in the initial question, definitions of emotional infidelity without sexual infidelity were more likely to mention being attached/dedicated emotionally to someone else (28 vs. 6 % in the initial question), performing non-sexual behaviors that create relationship problems (16 vs. 3 % in the initial question), quasi-sexual behavior (flirting, etc.) (8 vs. 2 % in the initial question), and having sexual/romantic feelings for someone else that were not (yet) acted on (19 vs. 0.3 % in the initial question).

Table 3 Percentage of responses coded for prevalent themes in response to the questions: “What is emotional infidelity?” and “What are some examples of emotional infidelity without sexual infidelity?”
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Overall, participants had more consistency in their definitions of what constituted sexual infidelity than of what constituted emotional infidelity (see Tables 2 and 3). This is evidenced by the higher numbers of definitions fitting into prevalent themes for both the definitions of sexual infidelity, as well as responses to the question “What are some examples of sexual infidelity without emotional infidelity?” In regards to definitions of sexual infidelity, 51 % of responses made some mention of sexual activity with an individual other than one’s partner and 20 % of responses contained the theme of physical sexual behaviors other than full sexual intercourse. Additionally, 52 % of examples of sexual infidelity without emotional infidelity fit into the theme of a lack of feelings or relationship intentions for a third party.

For definitions of emotional infidelity, the highest percentage of shared themes were 16 % for attending important events with someone else and 15 % for deceiving one’s partner about feelings towards them. Moreover, for examples of emotional infidelity without sexual infidelity 28 % fit into the theme of being attached/detached emotionally to someone, 19 % mentioned sexual/romantic feelings not (yet) acted on for someone else, and 16 % referred to non-sexual behaviors that create relationship problems.

Study 2

In order to expand on the findings from Study 1, Study 2 focused on examining how prototypical participant-generated responses were considered by a second group of raters. Due to the large number of responses provided in the first study, the second study selected to focus only on responses provided from one of the institutions involved in Study 1 (described below).

Participants

Definitions of sexual and emotional infidelity used in Study 2 were from those generated by one of the samples from Study 1: undergraduate students (N = 144; 81 % women, 18 % men, 1 % other; M age = 21.57, SD age = 4.04, age range: 18–40) recruited from a Northeast USA public university.

These definitions were then rated by a separate group of individuals (N = 73; 34 % women, 66 % men, M age = 29.07 years, SD age = 9.50, age range: 20–60) recruited from the online social networking site Facebook, through an event invitation. This recruitment strategy was employed in order to obtain a more diverse sample than the undergraduate students that are typically relied on for studies in this area. All participants were notified that the study was completely anonymous. No identifying information was collected nor compensation provided.

Materials and Procedure

The open-ended definitions of sexual infidelity and emotional infidelity rated in Study 2 were generated by participants from Study 1 following the procedure previously outlined. The open-ended definitions were not forced-choice responses, resulting in a different number of definitions provided for sexual (n = 99) and emotional (n = 88) infidelity. The average length of response (as measured by number of characters) was similar for definitions of emotional infidelity (M = 53.16, SD = 82.48) and definitions of sexual infidelity (M = 53.33, SD = 84.68). Comparing definition response rate by sex, women generated a total of 56 definitions for emotional infidelity and 60 for sexual infidelity whereas men generated a total of 9 definitions for emotional infidelity and 18 for sexual infidelity. One participant who identified their sex as ‘other’ generated 1 definition of emotional infidelity, and participants who chose not to disclose their sex generated a total of 22 definitions for emotional and 21 for sexual infidelity.

Definitions for emotional infidelity and sexual infidelity were compiled into a survey for Study 2 by eliminating repetitive responses. Examples of repetitive responses included identical responses (e.g., “Having feelings for someone other than your partner” was given by multiple participants) as well as content-identical responses (e.g., “Physically cheating on your partner” and “When your partner cheats on you, in any physical manner” were considered semantically identical). Some additional definitions were somewhat similar to others in the data, as can be seen in the tables. We made a point to include definitions if they were different in terms of some discernible facet from others that were included. In total, 68 definitions of infidelity (36 emotional, 32 sexual) were included in the survey.

Raters were presented with all 68 definitions of infidelity and were asked to rate the degree to which they agreed that each definition accurately depicted emotional and sexual infidelity on a Likert-type scale of 1 (strongly disagree) to 7 (strongly agree). In other words, participants in Study 2 rated how prototypical each definition was for sexual infidelity and emotional infidelity. Data for Study 2 were collected by a web-based questionnaire administered electronically via Survey Monkey (www.surveymonkey.com).

Analyses

Results were analyzed by examining the highest mean ratings provided by women and men in Study 2 for definitions of sexual and emotional infidelity. Additionally, between-groups t-tests were conducted on all mean ratings with participant sex serving as the independent variable.

Results

Recall that the participants in Study 2 were asked to rate the definitions created by participants in Study 1 in terms of how prototypical each definition was of sexual infidelity and of emotional infidelity. Overall, women and men agreed more on the definitions of sexual infidelity than emotional infidelity. This is evidenced by the fact that there were no significant sex differences in prototypicality for any of the sexual infidelity items. On the other hand, there were significant sex differences in two of the emotional infidelity items where in each case, women rated the item as more prototypical than men did, as discussed in detail in the following sections (see also Table 6).

Highest Ratings of Sexual Infidelity Prototypicality

For definitions of sexual infidelity, women and men had the highest ratings for the same 6 definitions, in a slightly different order (see Tables 4 and 5 for a complete list of definitions). Further, women and men had the highest ratings for the same two definitions. In these data, for both men and women, the highest-ranked definition of sexual infidelity was generated by a 19-year-old woman:

Table 4 Highest rated participant-generated definitions of sexual infidelity for women as raters
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Table 5 Highest rated participant-generated definitions of sexual infidelity for men as raters
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Sexual infidelity is when you are in a relationship or a marriage, and engage in sexual activity with another individual that is not your girlfriend/boyfriend, husband or wife. Having an affair, or cheating in a sexual manner.

There was not a significant difference between women (M = 5.76, SD = .44) and men (M = 5.73, SD = .50) on their prototypicality ratings of this definition. The second-highest-rated definition of sexual infidelity for both women and men was generated by a 26-year-old woman:

Sexual infidelity is claiming honesty and sexual exclusivity with one partner and then going behind their back or cheating with another partner.

There was not a significant difference between women (M = 5.76, SD = .44) and men (M = 5.70, SD = .50) in their prototypicality ratings of this definition.

Lowest Ratings of Sexual Infidelity Prototypicality

For comparative purposes, the definitions that received the overall lowest ratings of prototypicality for sexual infidelity for women and men are included in Tables 6 and 7. Overall, women and men had the lowest rating for the same definition generated by a participant who chose not to disclose age or sex:

Table 6 Lowest rated participant-generated definitions of sexual infidelity for women as raters
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Table 7 Lowest rated participant-generated definitions of sexual infidelity for men as raters
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Sexual infidelity is any action that you would not do with your siblings.

Additionally, women and men gave the second lowest rating to the same definition that was generated by a 21-year-old woman:

Sexual infidelity would include anything that would make one partner upset or uncomfortable.

Women and men did have some differences in the definitions of sexual infidelity that they ranked the lowest; however, these differences were not statistically significant. Specifically, women included in their lowest-ranked definitions the idea that sexual infidelity is “anything that results in an orgasm for either person involved” while men included in their lowest-ranked definitions the idea that sexual infidelity includes “any act intended or not, which causes or hints at possible sexual arousal up to actual sexual activity.” As previously mentioned, these results were not statistically significant, thus, caution should be applied when attempting to draw conclusions about these differences. However, it is interesting to note that women had lower rankings for a definition that claimed sexual infidelity must be limited to orgasms and men had lower rankings for the idea that sexual infidelity includes even the possibility of sexual arousal.

Highest ratings of emotional infidelity prototypicality

The highest-rated definition of emotional infidelity for women was generated by a participant who chose not to disclose age or sex:

Emotional infidelity is being “in love” or more dedicated emotionally to someone other than the partner, or family, someone with romantic potential.

The highest-rated definition of emotional infidelity for men was the second highest-rated for women. This definition was generated by a 21-year-old woman:

Emotional infidelity is when a person in a relationship creates an emotional distance by spending an excessive amount of time with, or thinks about, another person outside of the relationship, to the point that the other partner becomes ignored or rejected emotionally.

For definitions of emotional infidelity, women and men shared only two definitions in their top five highest rated (see Table 8 and 9). Further, two definitions were rated as significantly more prototypical by women than men. The first of these was generated by a 22-year-old woman:

Table 8 Highest rated participant-generated definitions of emotional infidelity for women as raters
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Table 9 Highest rated participant-generated definitions of emotional infidelity for men as raters
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Emotional infidelity is pretending you feel a certain way for your current partner when you really don’t feel that way most of the time and most likely feel that way for another person.

Men had a significantly lower rating for this definition (M = 4.46, SD = 1.20) than women (M = 5.08, SD = .91), t(71) = −2.27, p < .05, d = .58. Thus, men rated this item as less prototypical of emotional infidelity compared with women. The second definition that was significantly different for women and men, with women rating it as more prototypical of emotional infidelity, was generated by a 21-year-old woman:

Emotional infidelity is becoming attached to another with the intention of having a sexual relationship.

Men once again had a significantly lower rating for this definition (M = 4.08, SD = 1.50) than women (M = 5.04, SD = 1.24), t(71) = −2.74, p < .01, d = .70.

Lowest Ratings of Emotional Infidelity Prototypicality

The lowest-ranked definitions of emotional infidelity for women and men raters are included in Table 10 and 11. It is worth noting that the definition “I’m not sure what I would even consider emotional infidelity” was one of the lowest-ranked definitions for both women and men. This suggests that both genders agree that a tangible definition of emotional infidelity exists. Overall, there were no statistically significant differences between women and men’s ratings of the lowest-ranked definitions of emotional infidelity. These results indicate that while women and men had some disagreement about which definitions of emotional infidelity were the most prototypical, they shared similar attitudes in regards to which definitions of emotional infidelity were the least prototypical.

Table 10 Lowest rated participant-generated definitions of emotional infidelity for women as raters
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Table 11 Lowest rated participant-generated definitions of emotional infidelity for men as raters
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Discussion

There has been extensive research into the nature of infidelity (for a review see Tsapelas et al. 2010), highlighting the importance of infidelity in influencing the wellbeing of romantic relationships. Reactions to infidelity have been implicated as a major factor associated with divorce, violence toward women, and homicide (see Daly and Wilson 1988). That said, it is noteworthy that past studies have relied strongly on researcher-generated definitions of infidelity in the creation of stimuli. The current investigation was designed to address this gap, by qualitatively exploring how adults (i.e., non-researchers) in the USA describe and define acts of sexual versus emotional infidelity. By conducting a more nuanced exploration into the ways in which different forms of infidelity are defined, the current results provide a more informed picture of how people actually conceptualize these constructs. Although interesting at a face-value level, these results can provide more specificity for future research that seeks to explore the distinction (and overlap) between sexual and emotional infidelity, particularly in terms of sex-specific conceptualizations and reactions.

Overall, the majority of both women and men thought that emotional infidelity could occur without sexual infidelity, and that sexual infidelity could occur without emotional infidelity. However, both women and men were more likely to think that there could be emotional infidelity without sexual infidelity rather than sexual infidelity without emotional infidelity (see Table 1). Unsurprisingly, the most common theme for definitions of sexual infidelity was some mention of sexual activity with an individual other than one’s partner. When asked to provide examples of sexual infidelity without emotional infidelity, the most common theme was sexual activity with a lack of feelings or relationship intentions for the third party. The most common theme found in the definitions of emotional infidelity was attending important events with someone else, closely followed by deceiving one’s partner about feelings towards them. In the examples of emotional infidelity without sexual infidelity provided, the most common theme was being attached/dedicated emotionally to someone other than one’s partner. Taken as a whole, participants had more consistent themes in their definitions of what constituted sexual infidelity than on what constituted emotional infidelity (see Tables 2 and 3).

Together, the results converge with past work showing that women and men respond differently when given a forced-choice paradigm to report jealousy responses to sexual and emotional infidelity (e.g., Schützwohl 2004), but when the paradigm is not forced-choice (or modified to allow them to select both types of infidelity as equally upsetting), both sexes are upset by either form of infidelity (e.g., Lishner et al. 2008). This trend suggests there are features to each form of infidelity that are distinct but potentially overlapping, as has been suggested elsewhere. For example, DeSteno and Salovey (1996) argued that men may perceive women’s sexual infidelity as also signaling emotional infidelity because women are much less inclined to engage in sexual behavior without any form of emotional engagement. The authors further proposed that women may believe men can engage in sexual infidelity without emotional infidelity, but that emotional commitment implies some sexual activity. In another study, using forced-choice scenarios derived from Buss et al. (1999), but for the purposes of determining self-guilt, Fisher et al. (2008) posited that sexual and emotional infidelity are distinct but not mutually exclusive. The authors found that only one of the forced-choice scenarios, which pertains to emotional involvement with no chance of sexual involvement or sexual intercourse for one night with no chance of emotional involvement, men more frequently chose the latter option than women. They argued that this forced-choice item in particular captures the dichotomy between the infidelities, such that people rarely expect or seek emotional involvement from this type of interaction. As the authors review, given that men’s infidelity is more likely to take this form and involve someone of short acquaintance (Humphrey 1987), a key issue may be plausibility. Similar to the findings of the current study, Fenigstein and Peltz (2002) reported that, although both women and men believe each type of infidelity could occur independently, participants felt sex-only infidelity was more plausible for men and emotion-only infidelity more plausible for women. Thus, although these two types of infidelity seem distinct, the form of forced-choice scenarios may lead to sex differences partly because of plausibility.

One aspect of the current findings that is particularly thought provoking is how participants’ conceptualizations of sexual infidelity shifted when they defined it independent of emotional infidelity, and then when explicitly asked to define it in relation to emotional infidelity (see Table 2). The latter definitions of sexual infidelity without emotional infidelity were more likely to mention lack of feelings or relationship intentions for a third party, whereas when just asked what sexual infidelity is, participants focused instead on behaviors. Likewise, when participants defined emotional infidelity, their responses focused on behavior or on deception towards one’s partner, whereas when asked to define it independently of sexual infidelity, definitions focused on feelings towards someone else. What is consistent, then, is that when asked to define sexual and emotional infidelity, many participants focus on specific behaviors (including deception), but when asked to consider the types of infidelity as distinct from each other, participants focus on feelings. Therefore, the data suggest that many participants recognize that emotionality might be the core distinction between these two forms of infidelity. If so, this finding has many implications, as it may help to explain why the types of infidelity are often seen as distinct (e.g., do not include reference to the presence or absence of feelings) but overlapping (e.g., if items include mention of feelings). Furthermore, given the long history of research that suggests women are more emotional than men, whether it be due to socio-cultural or biological factors (see emotion regulation and infidelity, Amidon 2011), the fact that both sexes highlighted emotionality as central to their infidelity distinctions warrants further attention.

Facets of Sexual Infidelity

The present results indicate that women and men did not differ, on average, in terms of which definitions of sexual infidelity were most prototypical. As such, we can infer that when it comes to what sexual infidelity actually is in the minds of real adults, women and men seem to hold a shared understanding. Both women and men generated examples that included “sexual activity” that occurs with someone outside the pair-bond or “behind the back” of one’s primary partner. In short, based on the definitions participants provided in Study 1 and the prototypicality ratings of Study 2, sexual infidelity seems clearly and similarly defined by both women and men. A possible explanation for these results may be that physical acts are somewhat less ambiguous and simply more easily defined, and are, therefore, more distinctive than emotional acts.

Facets of Emotional Infidelity

According to the present findings, emotional infidelity, on the other hand, is more complex than is sexual infidelity. Conceptions of emotional infidelity seem more sex-differentiated than conceptions of sexual infidelity. Our content analysis of emotional infidelity definitions showed marked variability–including themes such as love and betrayal along with sexual infidelity or intentions to have sexual relations with someone outside the pair-bond. This emphasis on potential sexual activity as a component of emotional infidelity was particularly apparent in women’s definitions.

Prototypicality ratings for emotional infidelity differed across the sexes. It is particularly noteworthy that women were more likely than men to see definitions that included facets associated with sexual activity as highly prototypical of emotional infidelity. This finding is consistent with past research (e.g., Harris and Christenfeld 1996) showing that emotional infidelity is more conceptually complex than sexual infidelity and, further, that women are more likely than men to conflate emotional and sexual infidelity. Additionally, the definitions of infidelity that men ranked as the most prototypical tended to contain some theme of emotional abandonment (i.e., ignoring one’s partner emotionally) while this trend was not as apparent in the top-ranked definitions by women. Future research may benefit from exploring this theme further.

Limitations and Future Directions

This current research was designed to shed light on the way in which people, beyond researchers in the behavioral sciences, define sexual and emotional infidelity. Our participants provided definitions of each type of infidelity, leading to rich data on how men and women understand these concepts. Asking participants to also provide exemplars of each type of infidelity, as opposed to just providing definitions, leads to richer and behaviorally-based data. Therefore, future researchers may be wise to ask participants to generate exemplars of emotional versus sexual infidelity.

Due to the limited sample size and limited diversity–in terms of age and sexual orientation–a limitation of the current research is that there was not a large and diverse enough representation to assess these patterns across additional demographics. In terms of age specifically, the mean was approximately 21 and the standard deviation was approximately 5; a disproportionate number of our participants were young adults. For example, some recent research has found that the pattern of women being more distressed by emotional infidelity and men being more distressed by sexual infidelity is limited to heterosexual participants (Frederick and Fales 2014). Therefore, future studies will benefit from a broader, more representative sample that allows for additional demographic assessments. Moreover, the current study did not examine how participant’s previous experiences with infidelity might have influenced the definitions they provided. It would be worthwhile for future research to compare the definitions generated by participants who report previous encounters of either committing or having a partner commit acts of infidelity to the definitions provided by participants who report no previous experience with infidelity.

Further, this research is highly cognitive in scope, asking participants to essentially define concepts using their verbal skills. Perhaps further research into this topic could more deeply investigate the cognitive intensity of various scenarios and explore other psychologically relevant methodologies. For example, Kuhle (2011) had six coders analyze video stimuli of the syndicated reality television program Cheaters to determine if there was a sex difference in reactions to a partner’s emotional or sexual infidelity. Consistent with an evolutionary hypothesis, the coders found that women were more likely to focus on the emotional aspects of their partners’ infidelities, while men were more likely to ask about the sexual aspects. Similarly, researchers could utilize audiovisual stimuli from films that explicate infidelity, and participants could respond in terms of both self-reported ratings (a primarily cognitive task) as well as emotional reports. Such research might benefit, additionally, from including measures of psychophysiological response, including autonomic nervous system arousal, in response to infidelity stimuli.

The next step for the current research would be to create a validated scale based off of the highest-ranked definitions of emotional and sexual infidelity. This would then be followed by an analysis of which factors load onto which concept and a subsequent comparison to previous measures of infidelity. This new scale could then be utilized to replicate some of the previous findings on infidelity (e.g., Buss et al. 1999; Schützwohl 2004; Shackelford et al. 2002) to further address how infidelity is defined by researchers.

Overall, the current work suggests that researchers may benefit from using definitions of sexual and emotional infidelity that reflect the attributes identified in the highest-ranked definitions that were produced in this study as they provide more detail than previously utilized researcher-generated responses (e.g., “…having sexual intercourse with [a] person, but you are certain that they will not form a deep emotional attachment” or “Imagining your partner forming a deep emotional attachment to that person, but you are certain that they will not have sexual intercourse”; Buss et al. 1999, p. 132). Based on the results from this study, the best definition of sexual infidelity would be similar to the following:

Sexual infidelity is when a person is in a relationship or a marriage and engages in sexual activity with another individual that is not his or her girlfriend/boyfriend, husband or wife. Having an affair, or cheating in a sexual manner.

Although the definitions of emotional infidelity did show overall gender differences, the following definition was the highest-ranked for men and the second-highest ranked for women (the two highest-ranked definitions for women were very closely rated: 5.36 vs. 5.32) which suggests that both genders feel this is an accurate depiction of what emotional infidelity entails:

Emotional infidelity is when a person in a relationship creates an emotional distance by spending an excessive amount of time with, or thinks about, another person outside of the relationship, to the point that the other partner becomes ignored or rejected emotionally.

Additionally, researchers should consider that the current study found that women had significantly higher ratings than men for definitions of emotional infidelity that identified “pretending you feel a certain way for your current partner when you really don’t feel that way most of the time and most likely feel that for another person” and “becoming attached to another with the intention of having a sexual relationship.” These definitions suggest that there may be additional dimensions to what women perceive as emotional infidelity that should be considered by researchers.

Conclusion

Past research on the nature of reactions to infidelity has shed extraordinary light into how such reactions have significant social impacts (Daly and Wilson 1988; Harris 2003). Research on reactions to infidelity are part of a larger area of study, focused on addressing such issues as cognitive mechanisms that underlie infidelity reactions and sex-differentiated responses to infidelity-relevant stimuli (see Buss and Haselton 2005; Harris 2003). In short, the topic of infidelity, and in particular distinctions between types of infidelity, is a major area of social psychological and evolutionary psychological research and it is a topic with dramatic implications for individuals’ social and romantic lives, with further implications for clinical psychological research and practice. Continued studies into this area can provide clinicians with a richer understanding of how individuals define different forms of infidelity and also shine light on potential gender differences that may exist in these conceptualizations. By better understanding how someone interprets an act in terms of infidelity, clinicians and researchers may be able to acquire a more nuanced perspective that can aid in considerations of how individuals vary in their definitions of these constructs.

Previous research has been limited by the ways that past researchers have defined and conceptualized sexual and emotional infidelity, primarily in that they ask participants to respond to established concepts and definitions. The current research was designed to help provide clarity to these putatively different types of infidelity, by obtaining data from a wider range of participants on how they define and understand both sexual and emotional infidelity. Using a mixture of qualitative and quantitative methods, this research found that sexual infidelity is clearly conceptualized and that its elements are agreed upon by both sexes. On the other hand, these findings paint emotional infidelity as much more complex–and as having much less agreement between the sexes as to its elements. In short, emotional infidelity is a relatively complex phenomenon that is more likely to be interpreted in diverse ways as compared with sexual infidelity. Future research on infidelity will be improved with more accurate specificity and nuance by incorporating this point in terms of both research design and implementation.