Gurit E. Birnbaum, Ph.D.

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Our Fragile Relationships

What makes people more vulnerable to feeling attracted to alternative mates?

Posted Jan 28, 2019

Long-term romantic commitments typically fulfill love and intimacy needs and contribute to personal well-being. It is, therefore, of little surprise that people strive to maintain their relationships by employing strategies that help protect them against the allure of alternative partners. For example, in contrast to their single counterparts, romantically involved individuals tend to be less attentive to potential alternative partners, devalue their attractiveness, and show fewer signs of interest in interacting with them1. Unfortunately, such relationship-maintenance strategies are not always successful. Indeed, many relationships that were intended to last eventually dissolve, and even within relationships that endure, the rate of infidelity is rather high, with estimates of lifetime engagement in extra-relational affairs ranging from 20 percent to 70 percent2

Paolo Veronese/Wikimedia Commons
The allure of alternative mates
Source: Paolo Veronese/Wikimedia Commons

Research exploring the determinants of infidelity has mainly focused on personality characteristics that make people more prone to engaging in extradyadic affairs (e.g., attachment avoidance3, unrestricted sociosexual orientation). Relatively less is known about the relationship circumstances that lead people to stray from their current partner and the processes that drive them. Research4 published recently in Archives of Sexual Behavior has investigated the possibility that experiencing threats that are internal to the relationship and that stem from the partner’s hurtful behavior (e.g., expressing criticism, neglecting a partner's needs) lessens people's motivation to protect their relationship from the external threats implied by attractive alternative partners.

In four studies, my colleagues and I examined whether an internal relationship threat would undermine people's sexual desire for their current partners, thereby rendering them more vulnerable to feeling attracted to alternative mates and then acting on that attraction. In Study 1, romantically involved participants completed an online survey in which they indicated the extent to which they had felt hurt and disappointed by their partner lately. They also rated their sexual desire for their partner and the extent to which they had fantasized and flirted with alternative mates recently. Experiencing relationship threat was associated with lesser sexual desire for one's partner, which in turn, predicted more expressions of desire for alternative mates.

Study 2 sought to establish a causal connection between experiencing internal relationship threats and exhibiting more desire for alternative mates. To do so, partnered participants were asked to vividly describe either a time when their romantic partner had hurt them or a typical day in their lives. Then, they rated their sexual desire for their partner and evaluated pictures of attractive opposite-sex others, which were presented on a computer screen. Specifically, participants were instructed to indicate, by pressing the "yes" or "no" button, whether the pictured person might be a potential partner ("Do you consider this person to be a potential partner, irrespective of your current relationship status?"). We counted the number of selected partners to assess attraction toward non-partner targets, with a lower value indicating derogation of alternatives. The results showed that recollection of relationship threats led to experiencing lower sexual desire for current partners, which, in turn, predicted heightened interest in attractive alternative mates.

In Studies 3-4, participants underwent an experimental threat manipulation and then encountered an attractive stranger (a confederate). Their reactions during these encounters were recorded. In particular, Study 3 explored whether the effect of relationship threat on interest in potential alternative mates would manifest in observed approach behavior and hold true while interacting with an opposite-sex stranger, but not while interacting with a same-sex stranger. For this purpose, participants underwent a relationship threat manipulation and then interacted with either same-sex or opposite-sex confederates who ostensibly sought their help. We focused on the tendency to help an attractive stranger in need, because provision of help may function as a relationship-initiating strategy that is likely to seem more appropriate under the circumstances of a laboratory experiment than overt flirting, and thus is a less risky channel for expressing interest in alternative partners. 

Specifically, participants were led to believe that in the next 5 minutes, they and another participant would complete a questionnaire assessing their verbal reasoning. The experimenter introduced the confederate to the participants, seated them next to each other, told both that they were allowed to speak with each other while completing the questionnaire, and left the room. When the confederate ostensibly got to the third question, they turned to the participants and asked their help in solving that question, uttering, "I'm stuck with this question. Could you please help me in solving it?" Participants' helping behaviors toward the confederate were recorded using the following measures: the actual time spent helping solve the needed question, which was measured using a stopwatch hidden in the confederates' pocket, and the quality of the given help, as assessed by the confederate following this session. The findings indicate that participants invested more time and effort in providing help to an attractive opposite-sex stranger in need than to a same-sex stranger. This tendency to provide better and more help to an opposite-sex stranger emerged only under relationship threat. 

Although helping a stranger in need may serve as a relationship-initiating strategy, the meaning it conveys is not as clear as that of overt flirting. Study 4 addressed this limitation by examining whether a relationship threat would lead to actual flirtation with an attractive opposite-sex stranger. For this purpose, we experimentally manipulated a relationship threat and then introduced the participants to an attractive opposite-sex confederate who interviewed them about their attitudes toward interpersonal dilemmas (e.g., “Are you for or against playing ‘hard to get’ at the start of a relationship?”) while being videotaped. The videotaped interactions were coded for displays of flirtatious behavior toward the confederate interviewer (e.g., flashing seductive smiles, exchanges of penetrating gaze, petting one's body, and cocking head to one side). The results revealed that experiencing a threat to a current relationship is manifested in overt flirting with an attractive stranger, as can be observed by judges. 

Overall, our research demonstrates that partners' hurtful behavior diminishes the desire for these partners, directing attention, at least momentarily, to new, seemingly more promising relationships. Throughout their romantic life, people will almost inevitably encounter threats to the bond with their partner that arise both within and outside their relationship. Scholars have described several relationship-promoting responses for healing the resulting hurts, such as forgiveness or other intimacy-enhancing acts. And yet, people often respond to relationship threats by defensively distancing themselves from their partner rather than by employing these relationship-promoting strategies. The present studies indicate that when threats internal to a relationship arise, partners may become more vulnerable to feeling attracted to, and flirting with, potential alternative partners. Feeling sexually attracted to alternative partners may provide a means for partners to overcome their feelings of hurt. This attraction, however, may interfere with their ability or willingness to engage in relationship-promoting behavior.

This post also appeared here.

Facebook image: djile/Shutterstock

You may watch my TEDx talk on why humans make sex so complicated here. 


1. Lydon, J., & Karremans, J. C. (2015). Relationship regulation in the face of eye candy: A motivated cognition framework for understanding responses to attractive alternatives. Current Opinion in Psychology, 1, 76-80.

2. Blow, A. J., & Hartnett, K. (2005). Infidelity in committed relationships II: A substantive review. Journal of Marital and Family Therapy, 31, 217-233.

3. DeWall, C., Lambert, N., Slotter, E., Pond, R., Deckman, T., Finkel, E., Luchies, L., & Fincham, F. (2011). So far away from one’s partner, yet so close to romantic alternatives: Avoidant attachment, interest in alternatives, and infidelity. Journal of Personality and Social Psychology, 101, 1302–1316.

4. Birnbaum, G. E., Mizrahi, M., Kovler, L., Shutzman, B., Aloni-Soroker, A., & Reis, H. T. (in press). Our fragile relationships: Relationship threat and its effect on the allure of alternative mates. Archives of Sexual Behavior. ResearchGate