Why do guys always come back?

So this guy that I use to talk to we were fine I didn't know why we stop talking maybe because our scheduled was not the same so we barely had time for each other, but I find out overtime that  he had some other girl but that didn't go well for I guess she left him for another guy. So I'm very shocked that he came back to me. Should I feel bad about this idk I never thought he was going to come back to me 😔