Usually the reason for cheating is because of low self esteem. Often a man will cheat even on a beautiful successful wife, and they usually cheat with a woman that is "less than" what their wife is because the man wants to feel superior. I doubt the woman he met in that bar was anything like you, someone he felt better than to build up "his" self esteem is all he wanted. See, when you were so "hot" for each other, he was "the man", somehow he doesn't feel that way right now. That is also why the conversation has gone a bit "flat" too.

Men were designed to go off and hunt while the woman stayed behind, men gained their prowess from a successful hunt to bring back to his family, that has really remained the same with most men.

With you needing him to behave and him being "sorry" and you being the main provider, that is hard on him. No, he isn't feeling "playful", he is probably low and lost and needs to find something that helps him feel like "the man" again.

I am not blaming you or saying your being able to work and carry things financially means you are bad in any way. All I am saying is that he is probably struggling with how he isn't doing well right now.