Infidelity: The Unwelcome Personal Trainer for Jealousy and Control Freakery

Wednesday, March 12, 2025.

A new study confirms what every suspicious lover, every Facebook snoop, and every rom-com antagonist already suspected: if you imagine your partner cheating, you’re going to feel jealous.

And when jealousy sets in, you’re more likely to either drown your partner in affection or quietly install emotional barbed wire around them.

The research, published in Evolutionary Psychology, suggests that humans—sophisticated primates that we are—have evolved to respond to even hypothetical threats of infidelity with an intricate mix of tenderness and tyranny.

But before we pat ourselves on the back for being highly evolved, let’s be clear: this study isn’t uncovering the secrets of the universe.

It’s positing that, yes, we get a little unhinged when we think our mate might stray.

The same way one might clutch a bag of Doritos a little tighter after hearing about a chip shortage, our nervous system reacts to infidelity threats with protective instincts—some of them more useful than others.

A Little Evolutionary Background: Monogamy Is Weird, But Here We Are

While I tend to look at Buss et al.with a jaundiced eye, let’s examine their argument.

For most of our evolutionary history, parenting wasn’t a solo gig.

The presence of two (mostly) committed parents increased offspring survival rates, which meant that humans, unlike our more promiscuous animal cousins, developed long-term monogamous-ish relationships (Buss & Schmitt, 2019).

But with monogamy came the natural horror of realizing that one's partner might decide to sample the genetic buffet elsewhere. Enter jealousy—nature’s most inconvenient alarm system.

Jealousy, from an evolutionary standpoint, has served a protective function, ensuring that one’s investment in a partner (and potential offspring) isn’t squandered.

When faced with the possibility of a romantic betrayal, people generally react in one of two ways: by trying to strengthen the bond through affection or by attempting to lock things down with control (Bendixen & Kennair, 2017).

This study by Steven Arnocky and his colleagues aimed to poke at that mechanism by seeing how people react when forced to imagine their partner’s hypothetical dalliance. The results, while hardly shocking, add an amusing layer to our understanding of human nature: we are both deeply romantic and disturbingly possessive creatures.

The Study: TikTok, Jealousy, and the $1 Psychological Experiment

The researchers recruited 222 participants through MTurk, Amazon’s answer to "How do we get people to take psychological tests for the price of a vending machine snack?" The average participant was 33 years old, predominantly heterosexual, and undoubtedly questioning their life choices as they clicked through a study that paid them a crisp digital dollar.

Participants were divided into two groups.

The experimental group watched a one-minute TikTok video featuring a therapist gravely explaining how infidelity is rampant in committed relationships. They were then asked to imagine their partner falling in love with, sleeping with, and possibly sharing a Netflix password with someone else.

Meanwhile, the control group watched a far less emotionally taxing TikTok—just a negative food review.

They were then instructed to think about the heartbreak of anticipating a great meal only to find it disappointing. (A cruel manipulation indeed, but not quite as gut-wrenching as the thought of betrayal.)

After these exercises in masochism, participants answered questions about their current level of jealousy and how they might respond in the next month.

Their Options? The Classic Dichotomy:

• Benefit-Providing Strategies – Buying gifts, increasing affection, expressing love (the “please don’t leave me” approach).

• Cost-Inflicting Strategies – Inducing jealousy, issuing threats, attempting control (the “you’re not going anywhere” approach).

Predictably, those in the infidelity-threat condition reported significantly higher levels of jealousy, and that jealousy translated into an increased likelihood of engaging in both affectionate and controlling behaviors in the coming month. In short, when faced with an existential romantic crisis, people react like medieval feudal lords—offering riches or enforcing lockdowns, depending on their temperament (Davis et al., 2018).

The Science of Possessive Love: A Tale as Old as Time

These findings do tend to align with decades of research on mate retention strategies—the various ways humans try to keep a partner from straying.

In evolutionary terms, those strategies range from the sweet (gift-giving, bonding rituals) to the sinister (emotional manipulation, isolation tactics) (Shackelford et al., 2005).

The irony is that while some jealousy-driven behaviors can enhance a relationship, others can be profoundly destructive, leading to cycles of control, resentment, and, ironically, pushing a partner toward the very behavior they feared (Goncalves & Garcia-Marques, 2021).

Additional studies suggest that the way we respond to jealousy is often influenced by attachment style.

Allegedly, securely attached partners tend to favor benefit-providing strategies, whereas anxiously attached partners are more prone to cost-inflicting behaviors (Levy & Kelly, 2010). Meanwhile, avoidantly attached people pretend they’re above it all but will absolutely check their partner’s Venmo transactions when no one is looking.

Limitations and the Bigger Picture

While this study may contribute to our understanding of jealousy and mate retention, it does come with significant limitations.

For one, using MTurk means the sample may not be fully representative of the general population (Paolacci & Chandler, 2014). Additionally, the reliance on self-reporting raises the usual concerns—people are not always the most reliable narrators of their own emotions and behaviors.

Moreover, the study’s experimental design is fascinating but doesn’t capture real-life infidelity dynamics.

The difference between imagining a betrayal and actually discovering one is akin to the difference between watching Jaws and actually swimming with a great white shark (Guerrero et al., 2020).

Still, this research suggests a fundamental truth: jealousy, like fire, can either warm the home or burn it to the ground. The challenge for modern lovers is learning to harness it without becoming the human equivalent of an overzealous security system.

Love in the Age of Anxiety

Arnocky and his team provide further evidence that human relationships are a precarious balance between tenderness and paranoia.

Infidelity—real or imagined—activates a primal response that can drive us to express affection or, alternatively, make ominous comments about how everybody eventually leaves.

If there’s a lesson here, it’s that a little jealousy may be inevitable, but how we handle it determines whether our relationships thrive or become an arms race of control and desperation. Perhaps the best mate retention strategy is simple: be the kind of partner someone wouldn’t want to cheat on in the first place.

And perhaps stop taking relationship advice from TikTok.

Be Well, Stay Kind, and Godspeed.

REFERENCES:

Bendixen, M., & Kennair, L. E. O. (2017). Jealousy in relationships: A cross-cultural perspective on its functions. Personality and Social Psychology Bulletin, 43(6), 855-867.

Buss, D. M., & Schmitt, D. P. (2019). Mate preferences and their behavioral manifestations. Annual Review of Psychology, 70, 77-110.

Davis, A. C., Shaver, P. R., & Vernon, P. A. (2018). Attachment styles and romantic jealousy: The interplay of personal and relational factors. Journal of Social and Personal Relationships, 35(4), 523-546.

Goncalves, M., & Garcia-Marques, T. (2021). The effects of jealousy on relationship commitment: A meta-analysis. Emotion Review, 13(2), 134-150.

Guerrero, L. K., Andersen, P. A., & Afifi, W. A. (2020). Close encounters: Communication in relationships (6th ed.). SAGE Publications.

Levy, K. N., & Kelly, K. M. (2010). Attachment, jealousy, and relationship satisfaction. Psychological Bulletin, 136(1), 65-92.

Paolacci, G., & Chandler, J. (2014). Inside the Turk: Understanding Mechanical Turk as a participant pool. Current Directions in Psychological Science, 23(3), 184-188.

Shackelford, T. K., Goetz, A. T., & Buss, D. M. (2005). Mate retention tactics in married couples. Journal of Personality and Social Psychology, 89(3), 407-419.