And just a little note on men:

from my experience, the majority of men in our modern age are not mature enough to have a committed relationship before they are around 30, sometimes even older. What I mean by committed relationship is one that leads to marriage, children and so on, not just last a few years until they get tired of it and want to try something else. This is simply my personal opinion but this is what I have observed – there are obviously exceptions to that rule but I believe most men are not ready when they’re in their 20’s, especially early 20’s.

I also think it is important for both men and women to have some experiences before committing to one person and settling down, otherwise they might get doubts at some point and think that they might have missed out on something, be it sex adventures or relationships with other people.

I believe your ex is still deep in the adventure-experiemental stage of his life and that even if he did settle down with someone over the next few years, there is a good chance that he will cheat on her as he did with you. So don’t think that maybe in a year or two he’ll grow out of it…