I'm only guessing here, but I suspect that although you're working hard (and admirably) to meet his needs NOW, you weren't (admittedly) in the past, so he went and got his needs met elsewhere, and now he's just used to it. Like a "bad habit." I think he likes the thrill of another woman in his life, and has a hard time letting go of that now that his wife is working so hard to meet his needs.
