BOO, his heart isn't in it. he wants the younger woman and he can't have her (as 4get says), or he'd be off! they're going to stay friends, so there's no break. it's probably only a matter of time til they're back to where they started, in my opinion.. or he'll just be mooning over her forever. he's not putting his all into the marriage if he wants to stay friends with the lover. and does his wife know they're staying friends? I doubt it.
he hasn't chosen his wife, his other woman isn't offering him what (thinks) he really wants.