I've never had a ex return to me, ever. I feel like usually there's too much water under the bridge with an ex for things to ever be rekindled or move on like nothing's happened.
For example I was told that with my recent POI he will return, but I can't talk to him like nothing's happened after how he treated me and how long he has been out of contact. Things would need to be said and he wouldn't like this and after all the hurt and upset I could never forgive him.
It depends on how the relationship was like, ended, how bad things were and if the guy is fair and square. If he is narcy, then there's no hope of you being able to move on healthily as he will never see his faults and accept them. It depends if the guy is healthy or toxic, there's many factors involved... But like, 1% on this board get back with their exes and it's happily every after and smooth sailing.