The Biological Reason Why Breaking Up is So Hard

How our bodies talk us into getting back with our exes.

couple fighting with each other
(Image credit: iStock Images)

Over the weekend, a friend of mine broke up with a lady he'd been dating for a while. He liked her quite a bit, but had known for a while he didn't love her and that being with her forever wasn't what he wanted. Nonetheless, spending time with her was pleasant enough, so it took him a while to man up to bowing out. And in the end, the process may be nearly as painful for him as it's going to be for her.

When we hear about something like this, we may tend to think, "Oh, he's upset because he wonders if he's done the right thing, or if he should've stayed with her." Or we might say, "Oh, he's depressed because he doesn't like to see her sad." But, of course, he might also just miss her and miss their intimacy, even while knowing the relationship wasn't the end-all, be-all for him.

His experience reminded me of a paragraph I encountered in Attached: The New Science of Adult Attachment and How It Can Help You Find — and Keep — Love (opens in new tab), the new book by psychiatrist Amir Levine and social psychologist Rachel Heller, which I've mentioned before (opens in new tab).

They wrote:

"Attachment doesn't understand [that a romance can be] short run. In fact, attachment is a very powerful force — not just mentally and emotionally but physically, too. When you attach to someone, you're not as in control as you think. Therefore, it's not so easy to just break it off when you realize that someone isn't meeting your needs. People then stay for months or even years in an unhappy relationship — and it can take ages to get over a bad one."

None of that sounded too terribly surprising to me ... except for that bit about how attachment can be physically powerful. What exactly did they mean? I wrote them to ask.

In their response, they explained to me that back in the old days of cave women and hairy guys with clubs, people who got attached to others had an evolutionary advantage over those who didn't. If you were the type who got very close to someone, so that the two of you were always looking out for each other and checking in on each other (making sure neither of you was being cornered by a hungry saber-toothed tiger or something), that meant you had a better chance of surviving than someone who preferred to go it alone ... and risk running into a mammoth thug in a dark alley.

As such, the authors told me, "Our brain has been wired to make sure we remain connected to our mate." Multiple "reward circuits" in our noggins are involved in the attachment process, they said. "When we are physically close to our partner, the whole reward system kicks in — so that, for example, some parts of it secrete powerfully rewarding neurotransmitters that make being close to our loved ones an immensely rewarding human experience," they continued. "When we break up, this gratifying experience is gone, only to be replaced by a painful sense of loss. It feels a bit like going through withdrawal from several drugs all at once. And the one thing that can take all that pain away is being together with our ex again. This is why people find themselves getting back together again and again and why they can feel addicted to a person who may not be very good for them. In fact, these reward systems have a way of tricking us into reuniting with our ex to reduce the momentary anxiety and uneasiness. Unfortunately, this part of the brain isn't so good at making rational decisions and judging long-term consequences."

Doesn't that explain a lot about why you — or a certain friend of yours — can never seem to entirely put that sub-par boyfriend behind you? That information also seems to be a strong argument in favor of breaking up with someone you know you don't want to stay with forever sooner rather than later, instead of telling yourself, "Eh, it's fun. What's the harm? I'll run with it for a while." Don't you think?