I'm going to agree and say it's in your best interest to dump this guy and never look back.

Think about this: He says he loves you, he wants to be with you, and he wants to marry you. I don't mean this rudely, but what makes marriage with you so much different than marriage to his wife now? He doesn't seem to mind cheating on her...or already cheating on you. What makes you think he won't later on?

I hope that didn't come off as harsh. That wasn't my intention.

Additionally, I think he's baiting you. He's trying to implant the notion in your head that you'll never find someone like him (and for your sake, I hope he's right...he's scum). He blames your arguments on things you've done wrong. But when you comply, when you let him do what he wants, THEN he cares. That's not how it's supposed to work.

Truly, I think the best thing to do is go and never look back on this guy.