It's kind of complicated.?

That is complicated. It sounds like he likes you but he's probably not making a move on you because of his idiotic decision to leave you for your friend. And as complicated as your history is, all you really have to ask him is, "Why can't we give us a try again?" You don't have to put yourself on the line by asking that and it puts him on the spot to explain why he's not asking you out.