For millennia, humans have evolved in specialized ways to ensure their self-preservation. While we may not face the same threats that our ancient ancestors did, we still experience the effects of these evolutionary advancements every day. Jealousy, believe it or not, is one of them.
Our romantic partners offer us invaluable gifts—ones that are just as cherished today as they were millions of years ago. In early civilization, the promise of care, protection and offspring was an assurance of survival: that we, and our bloodline, could live on.
Although this sentiment may not carry as much weight today, the fear of “mate poaching”—or, as we call it today, infidelity—is just as prominent as it used to be. And according to recent research from Evolutionary Psychology, the thought of it alone is enough to impact the dynamics of a relationship.
Here’s how, according to the study.
The Origins Of The Fear Of Infidelity
The nuclear family structure relies heavily on monogamy to function. Since children—who offer us the greatest chance to continue our genetic line—are unable to care for themselves, many cultures rely on biparental care to facilitate their upbringing. Over time, and through evolution, this has led to a widespread preference for long-term, monogamous relationships.
While monogamy may be favored for different reasons in today’s age, it still presents us with similar challenges as it did our prehistoric ancestors—namely, in this case, the threat of partner infidelity.
For early humans, infidelity was a great risk to our livelihood, as it diminished our chances of reproductive success and safety. As such, jealousy is thought to have evolved to counteract these threats: it motivates us to protect ourselves.
Although infidelity may not immediately affect our chances of survival as it did back then, it can still strongly influence our emotional well-being and family structure. Therefore, jealousy—and the fear of our partners’ unfaithfulness—still play a significant role in our romantic relationships.
Measuring The Fear Of Infidelity
Given the evolutionary significance of jealousy and the fear of infidelity, the authors of the Evolutionary Psychology study—Steven Arnocky and his research team—were interested in how these two factors interact with one another in modern relationships.
To examine this, the researchers studied 222 participants, split into two groups. The first group were asked to watch a minute long TikTok that emphasized how common infidelity has become committed relationships.
Following this, the participants were asked to visualize their partners falling in love and having sex with someone other than themselves. The control group, on the other hand, were given food-related videos and visualization tasks.
Thereafter, the researchers measured each participant’s level of jealousy—as well as the frequency of their mate retention behaviors—over the month that followed. The researchers explain their eventual findings in an interview with PsyPost.
“Participants exposed to an experimental infidelity threat condition reported higher state jealousy scores than those in the control condition.” Continuing, they noted, “Jealousy, in turn, predicted more intended benefit-provisioning and cost-inflicting mate retention to be performed over the following month.”
In other words, when the fear of infidelity takes root, two common coping strategies can emerge. And while both may be valiant attempts to protect the relationship, they’ll more than likely backfire.
Here are the two harmful coping strategies that a fear of infidelity can create, and how they impact relationships.
1. Benefit-Provisioning: Love Bombing
When jealousy rears its head, some people respond by doubling down on affection. In practice, this often looks like a sudden, inexplicable and positive change in a partner’s behavior.
They might start showering their partner with attention, praise and acts of kindness in an effort to demonstrate just how great of a partner they are. On the surface, this might seem like a healthy way to handle insecurity—since, in their mind, it’s all about making their significant other feel valued and appreciated.
Eventually, however, problems will arise—specifically, once the other partner realizes how excessive or performative the behavior is. Over time, they may start becoming overwhelmed, confused or even suspicious of all the sudden attention they’re receiving. What’s supposed to come across as loving and supportive might instead feel smothering or disingenuous.
Of course, it’s natural to want to show your partner you care. That said, there’s a very fine line between healthy affection and desperately flailing to prove your worth.
At its core, love bombing in response to jealousy reflects a fundamental insecurity: the deep, underlying fear that you aren’t enough to keep your partner satisfied. When acts of love become a reaction to fear rather than a reflection of real love, it places immense pressure on one partner to constantly reassure the other. Over time, they may begin to resent feeling like they must constantly prove their loyalty or affection—which may miscarry into tension or even emotional distance.
Further, once a partner recognizes that the affection they’re receiving is motivated by insecurity rather than love, all forms of affection—genuine or otherwise—risk losing their true value. Over time, both partners may feel as though their love and affection for one another are just for show.
The only way to break this cycle is through self-reflection. Ask yourself: are you being affectionate because you genuinely want to make your partner feel loved, or do you crave reassurance for your own fears? If it’s the latter, addressing those insecurities head-on—even if it means you have to have a few uncomfortable conversations—will help you regain a sense of trust and safety within your relationship.
2. Cost-Inflicting: A Punitive Preventative Measure
The converse of benefit-provisioning would be cost-inflicting behavior: where jealousy pushes you to become more controlling, punitive or manipulative.
Instead of showering their partner with love—with the implicit hope of faithfulness—they explicitly ensure their partner’s fidelity, no matter the cost. They may begin monitoring their every move, questioning their intentions or even trying to make them insecure in return. This approach is rooted in a desire to maintain control; with enough of these preventative measures, the hope is that their partner will feel guilty or fearful enough to stay loyal.
For instance, they may start keeping tabs on their partner’s social life—demanding constant updates about their whereabouts, who they’re with and what they’re doing. They might think that keeping close tabs on them will guarantee them safety, but in reality, this kind of control almost always results in resentment and rebellion.
No one wants to feel like they’re constantly under surveillance. In this way, being treated like a teenager under curfew can threaten the very trust and security they’re trying so hard to shelter.
In other cases, the partner may even go so far as to emotionally manipulate the other—subtly implying that they’re not good enough to keep them happy, or that they need to “shape up.” This is usually done in the hopes that it lights a fire under the other partner—showing them what’s at stake, and that they’re a partner worth fighting for. However, this only results in both partners feeling insecure, with no way for either partner to resolve the real issue at hand.
Ultimately, cost-inflicting behaviors are driven by the all-consuming fear of abandonment or betrayal. Instead of addressing those fears directly, they manifest as attempts to control or manipulate the situation.
In the end, however, holding on too tight will only serve to push your partner further away. Much like with benefit-provisioning, it’s crucial to recognize that trust and security starts with introspection. Your fears are for you to work through; they aren’t something you can punish your partner for.
So, instead of letting the fear of infidelity consume you, use it to learn more about yourself, face your insecurities and strengthen your love.
Is the fear of infidelity present in your relationship? Take this science-backed test, and find out if it’s time to broach the topic with your partner: Emotional Jealousy Scale
