The study results also suggest that relationship status can play a role in people’s level of trust in cross-sex best friendships. Gilchrist-Petty wrote to me in an email that of all their findings, she was most surprised that engaged couples were the most skeptical. Engaged couples may be particularly protective of their relationships because they’re almost across the matrimonial finish line, she posited, “and do not want anything or anyone, including a cross-sex best friend, to potentially jeopardize their upcoming marriage.” In the study, she and Bennett also note that engaged couples are in a uniquely stressful situation compared with single, dating, and married people: Not only are they transitioning to become assumed life partners, they wrote in the study, “but they are often dealing with … merging lives and planning a wedding.” As they note in the study, this can include family problems as well as financial constraints, both of which are known to place long-term stress on people and relationships.

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Stress can certainly be a risk factor for feelings of jealousy, Solomon noted. “When any of us are under stress, we do kind of regress a bit, and fall back on less healthy ways of coping. Insecurity can spike, and if you’re not particularly comfortable in your own skin, you’re more likely to want to control the world around you,” she told me. “I think staring down this really big identity shift—a relationship-status shift, a life-commitment shift—just awakens insecurity that we don’t always know how best to cope with. So to get controlling of a partner would would just seem like a way of coping.” An unhealthy way of coping, to be sure, she added, “but it’s understandable.”

Solomon also lauded the study’s efforts to consider feelings of jealousy and expressions of jealousy separately. They’re often conflated, she told me—for example, the concept of a “jealous lover” is commonly invoked to describe both lovers who feel jealousy and lovers who exhibit controlling behaviors toward their partners. To consider the feeling of jealousy as something that may not necessarily have a corresponding action, she said, can help destigmatize it and clarify why people might be particularly vulnerable to it.

“Maybe this is another reason why engaged couples struggle the most,” she added. “When we fall in love and make a commitment to someone, we become actually, neurophysiologically tied to them. Our intimate partners live in our bones; they matter so much that they co-regulate each other’s physiology. So of course, [anything that gives] the sense of, Oh my God, I’m gonna lose you, is really threatening and terrifying. But that’s separate and apart from what you do with that.” In other words, she said, there’s a strong distinction to be made between I love you, and I’m reckoning with how much I need you and I love you, so I have to control you because I’m so afraid of losing you.