While I can understand how badly this hurts, a part of you should be so thankful this did not happen when you were already married with children, because that does happen.

This also happens to major celebrities too, beautiful women whom seem to have it all, end up being cheated on and divorce, some with children sometimes too. Also, he must have cheated on you, so he is a cheater, and cheaters can be quite charming you know. He will probably eventually cheat on her too, sounds like he is underneath it all, all about himself. Honey, you are best to be rid of him and find someone else. If he still kind of flirts with you, again, that is all for himself, don't buy that crap or fall for it at all or wish or hope either.

Find someone who will really appreciate "you" and has "respect" for you too.