When it comes to finding a partner, we’re hardwired to pick up on social cues that signal someone’s suitability as a mate—and one of the strongest signals is interest from others. That is, if we see that someone is attracting attention, we’re inclined to find them appealing too. But does this still apply once we’re already in a relationship? Do we continue to feel drawn to our partner if others find them desirable as well?
This is exactly the question that Gurit Birnbaum and her colleagues explored in their August 2024 study, published in The Journal of Sex Research. Their findings suggest that, once we’ve secured a partner, others’ attention toward them no longer boosts their appeal—in fact, it threatens it. Here’s how this phenomenon, dubbed by the researchers as the “flirting paradox,” can ironically weaken our desire, as well as diminish our investment in the relationship itself.
1. Mate Retention Strategies
Birnbaum and her team explain that humans, as products of evolution, are programmed to find a suitable partner. Since a “suitable mate” improves our chances of reproductive success, and is also crucial for both our personal and interpersonal well-being, it’s in our genetic code to try and find one.
However, it’s also noted that this process can be both time-sensitive and time-intensive (given our proverbial “biological clocks” and the difficulty inherent in finding a good partner), and potentially risky too. Thus, we tend to opt for mate recruitment strategies that minimize effort, while also providing reliable cues about a potential partner’s value.
Given our human tendency to take the path of least resistance, we rely on social cues when trying to find a good partner—such as seeing how they interact with others, and vice versa. One of these strategies is what is known as “mate choice copying,” which, as its name suggests, is when we observe others’ mate choices and imitate them.
Simply put, if others find someone attractive, we often follow suit—assuming their desirability has already been vetted—as a shortcut to finding a partner without investing unnecessary effort in further evaluation. But, this no longer applies once we’ve already found a suitable mate, and others start seeing them similarly.
Across three separate experiments, the research team found that individuals may start to see their partners as less attractive if they receive unsolicited attention from others. That is, we’re willing—if not happy—to witness flirting when we’re single, but not as much once they’re our partner.
As Birnbaum explains in a PsyPost article, “The meaning you attach to others’ attention changes once you’re committed to someone.” She continues, “When you’re single, external interest in a potential partner can serve as a valuable cue to their desirability. But in a committed relationship, that same attention may be perceived as a threat.”
Unsurprisingly, Birnbaum and her co-authors suggest that this “flirting paradox” also boils down to evolutionary mechanisms, particularly one known as “mate poaching.” Once our partner becomes the target of sexual or flirtatious advances, ample research suggests that our motivation to maintain the relationship weakens—suddenly resulting in us seeing our partner as a lot less appealing, and alternative partners as more promising.
2. Jealousy And Relationship Security
Witnessing our partners receive attention due to their attractiveness can, naturally, feel quite threatening to our relationships. With this in mind, we’re likely to be more observant and alert of “potential rivals” when we’re around our partners—both to monitor our rival’s intentions, as well as to make every possible attempt to keep our partners away from them. Thus, when we witness these advances—or even get the sense that someone might try to “poach” our partner—we inherently tend to feel jealous.
Jealousy, as we all know, can motivate us—especially in the case of mate poaching. Birnbaum notes that it’s not uncommon for us to opt for tactics that both protect our relationship as well as deter our rivals—like manipulating our partner to view the rival as a threat, or even outright attempts to intimidate or discredit the rival.
Oddly, we’re even inclined to employ these strategies when our partners don’t reciprocate the flirtatious advances; Birnbaum and her team suggest that thought alone of them returning the favor is enough to make us doubt their suitability and intentions. As time passes, this cycle of jealousy and doubt can cloud the view we have of how stable and happy our relationship is, which may in turn impact the relationship itself—as well as our commitment to our partners.
“The fear of losing a partner can trigger a cascade of defensive reactions,” explains Birnbaum. “To shield ourselves from potential pain, we might create emotional distance and withdraw investment in the relationship, hoping to soften the blow if our fears materialize. At the same time, the anger ignited by others’ interest in our partner can manifest as confrontation towards these perceived rivals,” she continues. She concludes by explaining, “These reactions, however, may be rooted more in retaliation than in genuine efforts to maintain the relationship.”
While we may rely on others’ flirtatious advances to scout for potential partners in the initial stages of a relationship, this strategy can paradoxically become our relationship’s demise in later stages. As the research suggests, once we already know that we have a valuable partner, we no longer need to be reminded of that by others. This kind of attention, once a relationship is well-established, only threatens us. Consequently, our evolutionary instincts—while protective in nature—may drive us to take drastic measures. But, in doing so, they can also undermine the very thing we’re trying to preserve.
Are issues like “potential rivals” always blown out of proportion in your relationship? Take this science-backed test to learn more: Relationship Sabotage Scale
