He cheated on his girlfriend with me multiple times and we have these intimate moments when we’re together but I don’t know what’s going on between us?

Well, what I would suggest is, do not be the third party in someone else' relationship. It is not a good thing at all is be involved in a triangle love, it is tough and unworthy of your time and effort. He may be in a confused state himself, not sure who he really wants to be with. You should do him a favor and leave him. No point trying to figure out what's going on between the both of you when it is not the right thing to be doing anyways.