Any person who has ever broken up after a long-term relationship is aware of exactly how difficult the experience can be. It is not something that one may easily put into words. If someone describes it as their heart being wrenched out of their chest and stomped upon in front of their eyes, it might be a tad dramatic, but not entirely untrue.
But as it so happens, initiating a break-up after a long-term relationship is also a terrifying prospect. And while an individual who has experienced both can testify that it is very different from the pain of being broken up with, the pain is real nonetheless.
Taking to Instagram on April 15, Jeff Guenther, a licensed professional counsellor based in Portland, shared five science-backed reasons to explain why the common act is always this difficult, even when a person knows in their mind why they need to break up.
1. Sunk cost and identity fusion
The longer the relationship, the more the identity of one person gets built around that of their partner. “Research says that your partner literally becomes part of your self-concept,” explained Jeff. “Leaving isn’t just losing them; it’s losing a chunk of you. It’s like losing your whole arm—just the whole thing.”
2. Intermittent reinforcement
Even in relationships that are not toxic, the ratio of good to bad periods creates what therapists call a variable reward schedule. According to Jeff, this is the same mechanism behind gambling addiction. “Your nervous system keeps betting on the good version coming back,” he shared.
3. Attachment theory and neuroscience
“This shows that separation from a long-term attachment figure activates the same brain regions as physical pain,” explained the therapist. “So when you think about leaving, your brain isn’t being dramatic—it’s genuinely registering it as a threat. That part of your brain will do absolutely everything it can to stop you.”
4. The oxytocin of it all
Oxytocin is a hormone and neurotransmitter produced in the hypothalamus that is popularly known as the “love hormone” for promoting trust, bonding and romantic attachment. In the case of long-term relationships, Jeff explained, “Years of physical closeness, touch, and hooking up mean your brain has been marinating in bonding hormones. Leaving means going cold turkey on a neurochemical you’ve had on tap for years. The withdrawal is frightening.”
5. Anticipated grief versus actual grief
Studies show that people overestimate how bad they will feel long-term after a breakup, noted Jeff. However, in that moment, “the imagined future devastation feels completely real and stops them from leaving.”
Note to readers: This article is for informational purposes only and not a substitute for professional medical advice. This report is based on user-generated content from social media. HT.com has not independently verified the claims and does not endorse them.

