It happens. You're scrolling late at night, a certain song comes on, or maybe you’re just feeling a bit lonely and that familiar name pops up on your screen. Before you know it, you’re considering sex with an ex. It’s one of those universal human experiences that people rarely admit to in polite company, yet statistics suggest a huge chunk of us have been there. In fact, research published in Evolutionary Psychology suggests that about half of young adults have engaged in some form of sexual activity with a former partner. It’s common. It’s messy. And honestly, it’s rarely just about the physical act.
We tend to tell ourselves it’s "no big deal" or "just for old time’s sake," but the psychological reality is a bit more tangled than that.
The Chemistry of Why We Go Back
Why do we do it? Is it just convenience? Sometimes. But usually, there’s a cocktail of neurobiology at play. When you’re with someone you’ve already been intimate with, your brain isn't starting from scratch. You have established neural pathways. There is a "history of reward."
Dr. Helen Fisher, a biological anthropologist who has spent decades studying the brain in love, often points out that the attachment system doesn't just switch off because a breakup happened. When you have sex with an ex, your brain releases a flood of oxytocin—the "cuddle hormone"—and dopamine. This can trick your system into thinking the relationship is viable again, even if your logical mind knows you broke up for a very good reason.
It’s easy. You already know what they like. They know your body. There’s no "first time" awkwardness or the need to explain your weird quirks. That familiarity is a powerful drug, especially when the dating world feels like a repetitive cycle of disappointing appetizers and ghosting.
Sometimes it’s about validation. A breakup is a massive blow to the ego. Returning to that familiar intimacy can feel like a quick fix for a bruised self-esteem. You’re proving to yourself—and maybe to them—that you’re still desirable. But that high is usually temporary.
📖 Related: Hairstyles for women over 50 with round faces: What your stylist isn't telling you
Is It Always a Disaster?
Actually, no.
While the cliché is that sleeping with an ex is a one-way ticket to Heartbreak City, the science is a bit more nuanced. A study led by Lindsey Rodriguez of the University of South Florida found that for many people, "hooking up" with an ex didn't necessarily result in lower well-being or more psychological distress.
For some, it’s a form of "soft landing." It tapers off the intensity of the breakup.
However—and this is a big however—the outcome depends entirely on your intent.
If you are using sex as a clandestine strategy to get back together, you are likely setting yourself up for a world of hurt. If one person sees it as a fun Tuesday night and the other sees it as "The First Step to Our Wedding," the fallout is going to be ugly. This is where the concept of "avoidant attachment" and "anxious attachment" comes in. Anxiously attached individuals often use sex as a tool to re-establish closeness, which usually backfires when the other person leaves the next morning.
👉 See also: How to Sign Someone Up for Scientology: What Actually Happens and What You Need to Know
The Physical Risk Nobody Mentions
We talk about the emotions, but let's get clinical for a second. There is a weird phenomenon where people assume an ex is "safe" because they know them. They stop using protection. They stop asking about testing.
This is a mistake.
Unless you have both been celibate since the breakup (unlikely) or have both been tested recently, you’re exposing yourself to the same risks as you would with a stranger. Don't let nostalgia blind you to basic sexual health.
Navigating the "Post-Sex" Clarity
The moment after is usually when the reality sets in.
In some cases, it provides "finality." You realize the spark is gone or that the reasons you broke up are still very much present. It’s like watching a movie for the second time; you notice all the plot holes you missed the first time around.
✨ Don't miss: Wire brush for cleaning: What most people get wrong about choosing the right bristles
But for others, it restarts the "No Contact" clock. If you were three months into healing and you have sex with an ex, you might find yourself back at day one, checking their Instagram stories and wondering why they haven't texted you back yet. You've reopened the wound.
How to Tell if You’re Making a Mistake
- The "Why" Test: Are you doing this because you’re horny, or because you’re lonely? There is a massive difference. If it's the latter, a vibrator or a night out with friends is a better choice.
- The "Morning After" Visual: Imagine them leaving at 8:00 AM. Do you feel peaceful, or do you feel a pit in your stomach?
- The Power Balance: If they were the one who dumped you, sleeping with them puts the power squarely in their hands. It can delay your ability to move on and find someone who actually wants to be with you.
What to Do Next
If you’ve already done it, don't beat yourself up. Shame is a useless emotion here. You’re human. You sought comfort in a familiar place.
If you're currently hovering over that "Hey" text, stop and breathe.
Immediate Actionable Steps:
- Check your triggers: Are you bored? Drunk? Vulnerable? Identify the emotion driving the urge.
- Set a 24-hour rule: If you want to reach out, wait 24 hours. Usually, the impulse fades once the dopamine spike subsides.
- Define the terms: If you must do it, have the uncomfortable conversation first. Ask: "Is this just sex, or are we trying to fix this?" If the answers don't match, walk away.
- Update your boundaries: If sleeping with them made you feel like garbage, it’s time to block the number. Not out of malice, but out of self-preservation.
- Prioritize your future self: Ask yourself if the 20-minute high is worth the three-week emotional hangover.
Moving on isn't a linear process. Sometimes it involves a few U-turns. The key is making sure those U-turns don't become a permanent detour that keeps you stuck in a past that wasn't working for you. Focus on the "why" and be brutally honest with yourself about what you're actually looking for. Usually, it's not the sex—it's the feeling of being known. And you can find that somewhere new, eventually.