Long before Katy Perry proclaimed that she kissed a girl and liked it, heterosexual-identified women were kissing other women. Although the phenomenon of female-female kissing isn’t particularly new, in the past decade scholars have turned their attention to better understanding the multitude of reasons why same-sex physical intimacy occurs between heterosexual individuals.

Generally when committed romantic partners kiss someone besides their partner, this is considered a form of cheating. Yet female-female kissing by heterosexual women does not seem to garner the same negative response, perhaps due to the varying reasons women report engaging in such behavior. Some heterosexual women report kissing other women as part of the college social scene or for men’s attention, while others do so to experiment or explore potential same-sex desires.1 A 2012 study found that both women and men perceive women who kiss other women in heterosexual spaces (for example, bars that heterosexual individuals frequent) as more promiscuous than those who kiss a man, and that women and men perceive such women as more likely to be heterosexual than bisexual or lesbian.2 In some ways, this last finding may suggest that women and men do not always perceive female-female kissing as necessarily an expression of women’s same-sex desire. So then what happens when individuals in heterosexual romantic relationships engage in more extreme forms of infidelity, such as sex, with someone of the same sex?

Evolutionary approaches to understanding jealous responses to infidelity suggest that women and men respond differently to infidelity based on varying evolutionary concerns. More specifically, research indicates that women are more jealous of men’s emotional infidelity (i.e., falling in love with someone) because they worry about losing the resources (such as food, money, love, support, etc.) provided by their male partners, and men are more jealous of women’s sexual infidelity due to paternity concerns (that is, a fear of investing in a child that may not be biologically their own).3,4,5,6 However, such frameworks do not consider what happens when there are sexual infidelities without the possibility of reproduction, such as same-sex infidelity.

To address this, an emerging line of research has explored responses to same-sex infidelity. Such research has revealed that women and men are less jealous of same-sex versus different-sex infidelity and that compared to women, men are more distressed by different-sex sexual infidelity compared to women.7,8,9 Conversely, women report being more upset by men’s same-sex versus different-sex infidelity.10

Most recently, we expanded this research to investigate a variety of emotional responses to same-sex infidelity, relational outcomes of such behavior, and communicative responses to jealousy (CRJs).11 CRJs are ways that individuals respond to jealousy, focusing on the idea that different responses are meant to communicate varying thoughts and feelings and help people reach various goals in their relationships.12 We asked our participants to read imagined scenarios that depicted a heterosexual partner cheating (by having sex) with someone of either the same or different sex, and then asked them to indicate how they would feel and respond to the infidelity if they were the partner in the scenario being cheated on. We found that men did not vary in how they expressed their jealousy in response to same-sex versus different-sex infidelity. Women, however, were more likely to deny they were jealous when faced with same-sex versus different-sex infidelity, and were more likely to publicly show that their partner was “taken” (e.g., by holding their hand or using pet names) as a reaction to different-sex versus same-sex infidelity. Our findings also suggest that concerns of losing a partner may be more strongly triggered by different-sex infidelity, and thus result in behaviors that publicly reinforce the relationship (which researchers call “signs of possession”).

We also found that men generally respond more negatively to a female partner’s different-sex versus same-sex infidelity, feeling more anger with different-sex infidelity and more sexual arousal with same-sex infidelity. Men also report that they would be more likely to end the relationship in response to different-sex infidelity compared to same-sex infidelity. Women also reported that they would feel more negative emotions (such as anger, hurt, and generally being upset) in response to different-sex versus same-sex infidelity, but women were more likely to report that they would terminate the relationship in response to same-sex infidelity.

How can we explain and understand these findings? First, these results may be related to the findings noted earlier regarding female-female kissing—the fact that there is not an equivalent framework for people to understand men’s same-sex sexual behavior (and that such behavior is less often depicted in the media) may mean that women have a difficult time accepting or acknowledging men’s same-sex infidelity. This may also mean that female partners may assume that a male partner who engages in same-sex infidelity may identify as gay, prompting the woman to terminate the relationship. Second, men may be more permissive of women’s same-sex infidelity due to the media’s fetishization of female-female sexual behavior and our society commonly depicting female-female displays of sexuality as being for men’s pleasure. So, to return to Katy Perry, our findings suggest that she is correct—her boyfriend probably “won’t mind it,” but if the tables were turned, Katy might not be so happy.

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Dr. Amanda Denes – Website

Communication, Feminist Studies emphasis, University of California, Santa Barbara

Dr. Denes is an Assistant Professor in the Department of Communication at the University of Connecticut. Her primary area of specialization is interpersonal communication, with emphases in disclosure, sexuality, and identity. Much of her work looks at the association between communication in interpersonal relationships and people’s physiological, psychological, and relational health.

Dr. Jennifer Bevan – Science of Relationships articles | Website/CV

Dr. Bevan’s research interests center upon interpersonal and health communication, including the negotiation of difficult interactions such as ongoing conflict, jealousy, sexual resistance, uncertainty, and topic avoidance, as well as related psychological and physical health correlates of these experiences.

Dr. Pamela J. Lannutti

Dr. Lannutti is an Associate Professor and Graduate Director in the Department of Communication at La Salle University. Her research focuses on communication in personal relationships, especially same-sex relationships. She is the author of Experiencing same-sex marriage: Individuals, couples, and social networks (2014, Peter Lang Publishing).

1Rupp, L. J., & Taylor, V. (2010). Straight girls kissing. Contexts, 9, 28–32. doi: 10.1525/ctx.2010.9.3.28

2Lannutti, P. J., & Denes, A. (2012). A kiss is just a kiss?: Comparing perceptions related to female–female and female–male kissing in a college social situation. Journal of Bisexuality, 12(1), 49-62. doi: 10.1080/15299716.2012.645716

3Buss, D. M., & Haselton, M. (2005). The evolution of jealousy. Trends in Cognitive

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5Scelza, B. A. (2014). Jealousy in a small-scale, natural fertility populations: The roles of paternity, investment and love in jealous response. Evolution and Human Behavior, 35, 103-108. doi: 10.1016/j.evolhumbehav.2013.11.003

6Symons, D. (1979). The evolution of human sexuality. New York: Oxford University Press.

7Sagarin, B. J., Becker, D. V., Guadagno, R. E., Nicastle, L. D., & Millevoi, A. (2003). Sex differences (and similarities) in jealousy: The moderating influence of infidelity experience and sexual orientation of the infidelity. Evolution and Human Behavior, 24, 17-23. doi: 10.1016/S1090-5138(02)00106-X

8Hughes, S. M., Harrison, M. A., & Gallup, G. G., Jr. (2004). Sex differences in mating strategies: Mate guarding, infidelity and multiple concurrent sex partners. Sexualities, Evolution, & Gender, 6, 3-13. doi: 10.1080/14616660410001733588

9Sagarin B. J., Becker D. V., Guadagno, R. E., Wilkinson, W. W., & Nicastle, L. D. (2012). A reproductive threat based model of evolved sex differences in jealousy. Evolutionary Psychology, 10, 487-503.

10Weiderman, W. W., & LaMar, L. (1998). “Not with him you don’t!”: Gender and emotional reactions to sexual infidelity during courtship. The Journal of Sex Research, 35, 288-297. doi: 10.1080/00224499809551945

11Denes, A., Lannutti, P. J., & Bevan, J. L. (2015). Same‐sex infidelity in heterosexual romantic relationships: Investigating emotional, relational, and communicative responses. Personal Relationships, 22(3), 414-430. doi: 10.1111/pere.12087

12Guerrero, L. K., Andersen, P. A., Jorgensen, P. F., Spitzberg, B. H., & Eloy, S. V. (1995). Coping with the green-eyed monster: Conceptualizing and measuring communicative responses to romantic jealousy. Western Journal of Communication, 59, 270-304. doi: 10.1080/10570319509374523