Broken Up But Not Forgotten

Behavioral scientists and relationship experts have amassed a considerable body of research related to the “on‑ramp” of courtship processes (searching, dating, and mating). But by comparison, much less is known about the bumpy “off‑ ramp:” when people exit romantic and sexual relationships, willingly or otherwise.

In the digital age, our intimate past lives can live on in ways that make it harder for some of us to move on; nearly half of men and a third of women will hold on to sexually explicit photos of their ex after a breakup. And sometimes staying connected can reignite our remaining passions, as with our data showing that one in five singles has gotten back in touch with a former partner after their ex liked something they posted on social media.1

Behavioral theorists have developed various hypotheses to explain why we can’t stop ourselves from staying connected to or checking up on our exes. More and more, I have come to believe that romantic love makes an indelible imprint on the mind, and when a breakup occurs, it leaves a scar. I mean this both metaphorically and literally— as we’ve seen in fMRI studies conducted by my colleague Bianca Acevedo and others, specific patterns in brain activation associated with long‑ term romantic love suggest that these relationships leave residual marks on the brain. Once we have loved someone, a little bit of them stays with us forever. In many ways, this is nature’s price of intimacy.

I have a friend who can’t smell fresh lavender without it triggering the bittersweet memory of a two‑ decade‑ old teenage crush, and another who gave up cigarettes years ago but still loves the lingering scent of smoke on other people’s clothes because it reminds him of an ex.

The bonds we forge with a romantic partner don’t get wiped away when the relationship ends, as evidenced by the stunning finding that half of the participants in one of our studies said that they have had an on‑again off‑ again relationship at least once in their lives. Our research team has come up with a number of compelling practical reasons we might return to an ex: they’re a known quantity; it doesn’t add to our “body count” of partners; it’s easier than reentering the mating market; a part of us still loves them.

Fundamentally, I believe this form of relationship yo‑yoing is a byproduct of the strength of pair bonds. It’s similar to why we see so much recidivism when it comes to drug use: Our partners get us high on romantic love, which makes us feel good, and we become habituated. Then, when we lose access to the source of that rush, we go through withdrawal while we relearn how to live without them. And many of us won’t make a clean break on the first try.

Evolutionarily, there is a good reason it is emotionally difficult to walk away from romantic bonds. Once we’re out of

that courtship stage and pulled closer and closer into each other’s gravitational orbit, the attachment and commitment ties between us grow tighter, and it becomes biologically, psychologically, and sociologically difficult to uncouple — even more so when children and other family members are involved. We become entangled in each other’s lives, which is perhaps a feature, not a bug, of having to ­ pair‑ bond for survival and reproduction.

Relationships end for a host of reasons. One ingrained judgment that many people have is thinking about all past relationships as failures: a damaging myth I’ve become practically militant about dispelling. The reality is that just because a relationship ends, that doesn’t mean it failed.

Almost all of us will at some point experience lost love, and for many the pain that comes with such loss. But so often we find love again. And sometimes we land on something that feels comfortable and intimate, and that can be enough.