Picture the scene: You’re in a relationship. And out for lunch with a good friend. The conversation turns to love, romance, commitment. And out of nowhere, your friend asks you a simple but profound question: ‘Why are you in a relationship?’

You’re taken aback. That question can be taken many ways, after all. ‘What do you mean?’

They hasten to clarify themselves. ‘I mean… Why are you in a relationship rather than not in one? What is it that keeps you together?’

It’s not a loaded question—but it’s a hell of a conversation starter. You sit back and ponder. Is it passionate love? Obligation to commit? Fear of being alone? And conversely, if you’ve been seriously considering ending the relationship—why? Fed up with your partner? Feeling uncared for? Just… not in love anymore?

Then you land upon the reason. ‘Well…’

Well indeed. That’s where the scene ends because only you can fill in the blank. And the answer might be even more important than you’d think. Because according to new research, there are literally thousands of reasons people cite for staying in their relationships. But according to the psychologists behind it, a grand total of two of those reasons truly matter.

The interdependence theory of relationships

The holy grail of relationship research is finding a variable that predicts, with clinical precision, whether a romance will last and “succeed”—however you might define that. But barring this essential impossibility, scientists aim to at least identify the key psychological elements that keep couples happy and satisfied. The available theories guiding much relationship research propose a number of factors, such as equity (getting the same out of the partnership as you put in) and exchange (the benefits clearly outweighing the drawbacks).

But given the competing proposals about what truly makes a relationship tick, you’d be forgiven for believing this theoretical knot is simply too intricate to unravel. In fact, according to 2021 research from Laura Machia of Syracuse University and Brian Ogolsky of the University of Illinois at Urbana–Champaign, it seems unlikely that there exists any single factor that could predict relationship success beyond “a modest amount of certainty.” They also note that the reasons people stay in relationships aren’t always the polar opposites of the reasons they leave.

With this in mind, the researchers set about separating the stay reasons from the leave. They recognized that “people in relationships may experience competing motivations,” which “may be driven by independent reasons.” And according to interdependence theory, it’s not enough to look only within the relationship to ascertain people’s reasons for staying or leaving. Because no partnership exists in a vacuum; we’re all surrounded by people of every stripe—including those who could be a potential romantic partner… “in another life.”

In other words, we must also account for a person’s expected outcomes from their relationship and the inevitable cost–benefit analysis that will be playing out in their head when an attractive alternative comes into view. In the psychological parlance, this is dissolution consideration. You might think of it as the inverse of commitment to remain in the relationship and researchers found a surprising lack of studies on the concept.

Two motives supersede all others

Machia and Ogolsky put interdependence theory to the test on a sample of undergraduates, all of whom were in relationships. They found that reasons to stay were indeed not solely the opposites of those to leave—but more importantly, they identified the two reasons—one to stay, one to leave—that trumped the others by a mile:

  1. Reason to stay: passionate love tied to a profound sense of commitment
  2. Reason to leave: the availability of an attractive (and feasible) alternative

While these findings were a solid initial confirmation that stay–leave decisions don’t operate along a single dimension, the researchers wanted to put interdependence theory to a more stringent test. They recruited couples of a much broader age range and interviewed them over nine months, conducting periodic tests. Participants were asked how they felt on that particular day about the prospect of marrying their partner, as well as whether their commitment had grown or waned since their last interview. The pivotal question: Would these fluctuations align with people’s reasons to stay or leave, as they had in the original undergraduate sample?

The interviews produced an almost incomprehensible 15,117 reasons for turning points in the participants’ relationships. The coding team eventually pared these down to 14,000, classified into 14 categories. The most frequent category of reasons for increased commitment pertained to positive attributions of the partner or relationship, while the most frequent category for contemplating a breakup was the availability of someone else which is consistent with interdependence theory.

The grass isn’t always greener

What might these findings mean for your own relationship? Think back on its highs and lows over just the last few weeks. You might not be able to identify fifteen thousand reasons to stay or leave—but 15’s probably not much of a stretch. Perhaps you fantasized about a beautiful stranger sweeping you off your feet. Perhaps that person wasn’t even a stranger, but an acquaintance, co-worker, or even a friend. And perhaps the feeling was so strong that all reasons to stay just faded into insignificance.

But before abandoning ship, Machia and Ogolsky recommend caution and that you return to your column of stay reasons. Is this reason to leave just a transient and fleeting fairytale? Is it distorting your perception of a relationship that’s actually healthy, vibrant, and flourishing? And reflect, too, on the reasons you got together. To what extent do they still hold true? And how many of your needs being fulfilled in the present would be left wanting if you split up in the future?

Being tempted to leave can be a natural consequence of a bad patch in a relationship, and you shouldn’t beat yourself up over it. And it in no way necessarily means your romance is destined for a downward trajectory, either. What’s more, it’s vital to always keep in mind that your relationship is a two-person commitment: Understanding your partner’s reasons to stay can be just as important as sifting through your own. Honesty, transparency, and communication are key. Whatever path you ultimately choose, be certain you’re doing it for the right reasons. That’s where we can help.

Maclynn International is an elite, multi-award-winning matchmaking agency with offices in New York, California and London. Our matchmakers aren’t only experts at bringing together highly compatible singles, but also relationship specialists in their own right. We’ve helped thousands of people find lifelong love in happy, satisfying, and meaningful relationships—and we can help you, too. Get in touch today, and let’s pinpoint your reasons—be they to stay, to leave, or to sit your partner down and open up about how you truly feel the relationship is going.