zuzu wrote:"He acts EXACTLY like someone who has recently been cheated on."
That is typical of the syndrome, even when there was no actual infidelity.
Quote:"I said, "to prove to you that you're the one I really want to be with and I'm passionate about you." "
That is where you need to start the exploration. I think that the sexual acts are just proofs for him. His issue seems to be rooted in his insecurity about how and why you came back to him. Explaining to him in detail why you wanted him and not the other(s) may be a good start. If you believe you were wrong to have ever left him, then you need to let him know.
You can't alter the facts, but you can give him something to hang an anchor on. Above all else, be honest. The smallest omission or lie will kill the process. He has to believe that you PRECISELY "get it" before he can turn loose.
Make sure that you don't get frustrated and angry with him. He wants to not feel this way, more than you know.
After this is all dealt with, then if there is an affair in some form, you can deal with that, if it doesn't just self-resolve (which is likely).
All the best, -NOPkins-
I will ferret out an affair at any opportunity.
-An affair is the embodiment of entitlement, fueled by resentment and lack of respect. -An infidel will remain unreachable so long as their sense of entitlement exceeds their ability to reason.