Wishing, I think he's waiting for you to loose it and toss him out. That way he doesn't have to be the bad guy. This is probably not helping S in school much, with how quickly you can be preoccupied.
I was just as dumbfounded about why my H decided to stay and you are about your h's lack of direction. That is probably the most difficult part - you cannot start healing anything, not your heart and not your marriage.
I often think of you.