If you initiated the breakup, remember that you did it for a good reason. If you did not initiate the breakup, well... That's a lot harder. I know it's easy to fall down that slippery slope of thoughts; thoughts like "We were meant to be together," "S/he was perfect," "If they knew how much I care about them," "We could make this work if s/he would give me another chance." These thoughts are natural, but they're not necessarily true. Odds are good the other person had a good reason to break up with you--even if they didn't tell you what it is. Or, if they did and you think it wasn't a good reason, well, it must have been to them. You may never know or understand the reason. For me, this was the hardest part. You have to accept that answers may never come. No amount of googling "how to get my ex back" will help you move on. When they get a new SO--and they will--no amount of Facebook stalking, jealousy, or judgmental condescension is going to break them up. The real fact is, even if you've lost the ability to imagine a future without someone in it who is no longer part of your life, you eventually have to come to the realization that the future comes regardless and we need to adjust course accordingly. Some people recommend jumping right back into the dating pool or getting laid as a way of forgetting or moving on, but I've never found rebounding to be particularly helpful or rewarding. I find it's better to resign yourself to singleness, allow yourself to feel the pain and the loss of the break up, and let your feelings take their course. And maybe some day, you realize someone else is making you feel the way that your ex once did--or completely different, but in a good way. And it's okay to be happy with some one else, even though moving on can sometimes feel like betraying or cheating on the person who broke up with you. You have to realize, though you're used to directing affection and devotion to that one person, but you don't owe it to them anymore. They gave you permission to love someone else when they left. Even so, it's also okay to miss your ex. It's okay to remember their quirks, their endearing imperfections, and to allow yourself to wonder what life would be like if you'd stayed together. But after a while, you stop hoping that life will be that way some day, and instead it becomes purely hypothetical. I guess what I'm saying is there's no cure but time, and it's often slow and incomplete. You don't wake up one morning and realize you're over your ex. But as impossible as it may seem right now, you can start moving on a little more each day. And who knows? Maybe one day, you'll look back on that relationship and realize that you are over it, and you're a stronger person because of it, and you may even be glad it happened. TL;DR: You just do.