This Psychological Theory Explains Why a Breakup Is Destroying Your Sense of Self

Breakups can feel debilitating — they’re mentally taxing, heart-rending, enervating experiences that can induce intrusive thoughts, depression, loneliness and even a loss of sense of self, all of which can manifest physically (read: insomnia, weight gain, hair loss and even reduced immune function).

In a word, breakups are brutal. And they take time — often, a lot of time — to move on from. This is especially true when you feel like you've lost yourself in the breakup, as though you don't know who you are without your ex-partner. Because, after all, you may have felt like your ex-partner or, rather, your "other half" had "completed" you. You experienced self-expansion with this person.

Self-expansion theory, a wealth of researchers suggest, is perhaps exactly why some breakups seem to suck so much. Self-expansion theory is based on two key principles:

1. We, as humans, have a primary motivation to self expand in life.
2. We can achieve self-expansion through close relationships with others that allow those others to be part of ourselves.

Relationships are exciting because, when we're in them, we learn a lot — much of which is about our own selves. We take on new challenges, we try out new hobbies and we experience a whole lot of newness that helps us to find and define ourselves. It feels a lot like we expand our sense of self and, sometimes, like we can finally be our true selves because our partners tend to bring out the best in us.

"This isn’t about minimizing your own tastes and hobbies, and it certainly is not an argument in favor of taking on your partner’s identity and casting aside your own," writes Melissa Dahl for The Cut. "(It is probably still a good idea to, for example, know what kind of eggs you like.) Rather, it’s about that notion of self-expansion, of introducing new perspectives and experiences into your life. It makes life meaningful, yes. But it can also make life more fun."

In fact, in 1993, Arthur Aron, a professor of psychology at Stony Brook University, published a study that suggests that couples who spend more time together doing new and exciting activities are more satisfied with their relationships. In 2000, Aron and his colleagues duplicated a similar study and found the same telling results — couples who try new things with one another are simply happier. This is largely because they feel as though they've grown together.

Of course, you can try new things on your own to expand your sense of self in other ways — but few ways are as reliable as a romantic relationship.

"There are, of course, many things that promote that feeling of growth," Dahl goes on. "As you get older, you encounter countless identities that you could bundle into your own: You could become a runner, a painter, a writer, a vegetarian, a spouse, a parent. But, according to the psychological literature, one of the most reliable ways to achieve self-expansion is by beginning a new romantic relationship (or investing energy into a long-term one, so that it feels like new)."

And this is why breakups can be so physiologically devastating. A breakup is not only a split with a partner, but it also halts the self-expansion we'd experienced in that relationship. 

Research suggests that, when on the brink of a breakup, our self-concepts diminish.

So what can you do to move on from heartbreak?

"Focus on restoring your self-concept, either by doing the things you loved and lost sight of during your relationship or by trying out brand-new hobbies," Dahl writes. "This is common-sense breakup advice, but typically it’s a tactic meant to distract yourself from your heartbreak. And it will probably do that, and that can help. But when you drag your brokenhearted self to the guitar lessons (or whatever) that you’ve secretly always wanted to take, you’re also rebuilding the you you just lost."

In short: Get out there and find yourself again. It may sound like cliché advice, but it's cliché for a reason.

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