Someone flirts with your spouse. Does that make your partner appear more attractive?

Picture this: You’re at a bar when someone starts hitting shamelessly on your spouse or significant other, who doesn’t flirt back. As the scene unfolds, your base instincts kick in—annoyance, anger, jealousy—followed by a heightened sexual desire for your partner. You’re ready to reclaim the attention that should be rightfully yours, correct?

Not necessarily, according to a new study in the Journal of Sex Research by researchers at Reichman University in Herzliya, Israel, and the US-based University of Rochester. Instead, the researchers discovered a surprising twist: despite the fact that your significant other did not reciprocate the advances, your own attraction to your partner begins to wane, and your desire to continue investing in that relationship diminishes.

At first glance, the reaction seems paradoxical, notes the study’s lead author Gurit Birnbaum, a professor of psychology at Reichman University. A substantial body of prior research has shown that when searching for a partner, we frequently rely on social cues. One such cue, known as mate choice copying, occurs in both humans and animals. Think of it as a shortcut to identifying desirable partners: seeing others interested in a potential mate often makes that person appear more attractive and desirable.

But the simplified formula of “more attention equals more desire” doesn’t seem to apply to established relationships.

”The problem is, once we have established a relationship, we become concerned about something called mate poaching—the idea that a competitor might lure our partner away,” explains coauthor Harry Reis, a professor in Rochester’s Department of Psychology and the University’s Dean’s Professor.

While the bulk of earlier research has largely focused on the initial stage of mate selection and the start of new partnerships, this latest study looks at the effects of unsolicited flirting on an established relationship.

Research has shown that people tend to use a mix of positive and negative approaches to keep their partners close. Giving gifts and spending quality time together are examples of positive tactics, says Birnbaum, while controlling a partner’s time is a negative approach.

“While some might try to make their partner jealous by seeking attention from others, possibly to feel more desired or secure, our research shows this tactic often backfires.”

What happens next is important.

“When a partner’s likelihood of being attracted to someone else is perceived as high, such as when they receive attention from others, people tend to abandon the positive tactics,” says Birnbaum.

Indeed, the fear of losing a partner may trigger a cascade of defensive reactions designed to protect us from hurt, including emotional distancing and withdrawing investment in the relationship, hoping to soften the blow if our fears materialize.

These defensive distancing responses, says Birnbaum, are designed to avoid a “potential blow to one’s self-esteem from rejection rather than risk further attachment to a partner whose commitment could be compromised by rival suitors.”

Three experiments put unsolicited flirting to the test

The team tested Israeli participants’ reactions across three separate experiments, using visualization, virtual reality, and recall techniques.

Participants in all three studies were in monogamous, mixed-sex relationships of at least four months. They were exposed to situations in which their real-life partners received unsolicited flirtatious advances. (All three experiments used control groups in which the participants’ partners encountered a neutral interaction with another person). Then, participants rated their sexual desire for their partner, their interest in deterring potential rivals, and their own relationship-maintaining efforts as expressed, for example, in the kind act of taking over a chore for their partner.

For the first experiment, 244 participants (126 women, 118 men) were asked to imagine a scenario where someone else showed interest in their partner (without the partner’s reciprocation), or interacted neutrally (for the control group). Next, participants were instructed to describe a sexual fantasy about their partner in a narrative format. Independent raters coded these fantasies for expressions of desire for the partner and the degree to which participants prioritized their partner’s pleasure over their own sexual desires. The team considered lower values as signs of defensive distancing and sexual disengagement.

In the second experiment, the researchers used virtual reality to create a realistic, yet controlled environment to study participants’ reactions to unwanted attention towards their romantic partners. To that end, 132 undergraduate students (66 women, 66 men) put on VR headsets and were transported to a bustling bar where they watched their real-life partners interact with a virtual stranger, who either flirted with their partner or remained neutral. Using VR, the team was able to create a safe environment to study the very real emotions of jealousy and possessiveness—without the risk of study participants’ coming to blows or causing a bar brawl.

In the third experiment, 190 participants (101 women and 89 men) were asked to recall and describe a past episode in their relationship where someone had either expressed unreciprocated interest in their partner or had interacted with their partner in a neutral manner.

The team found that study participants reacted to a stranger’s showing interest for their partner by feeling less desire for their partner, a reduced interest in investing in the relationship, and an increased interest in thwarting potential rivals.

Flirt at your own risk

The study’s biggest takeaway for your everyday romantic life? “Don’t flirt with others if you want your partner to be happy with you,” says Reis.

“While some might try to make their partner jealous by seeking attention from others, possibly to feel more desired or secure, our research shows this tactic often backfires,” echoes Birnbaum. “Instead of strengthening the relationship, it can damage the very connection it aims to enhance.”

The study is supported by the Israel Science Foundation, the Binational Science Foundation, and the European Union’s Horizon 2020 research and innovation program.