Sounds like a guy who is very experienced at having affairs with younger women.
Giving just as much as they need to get hooked,but not so much that he feels guilty.
He hasn't left his wife yet, so it's a safe bet he won't. So that's one less thing to worry about.
It is perfectly possible to be possessive of more than one person at a time, that doesn't mean anything.except his cheating has made him insecure the same will happen to him.
I suspect he likes the idea of his mistress falling in love with him, but deep down doesn't really want things to be that complicated.
Either way he is going back to lay with his wife after dipping it in his mistress, and vice versa, so in my book a scum bag.