my 16 year old is so angry

My 16 year old son is so angry since he's caught his father in another lie. There has been alot of misery in the house for over 16 years. I only stayed in the marraige thinking it was the best thing for my son. Last Saturday I had enough when I saw how upset my son was over a lie his father made up about me..........he insinuated that I must be a whore since I stayed out all night with my boss and his step mother almost 18 years ago......which was only a month after meeting my husband. The malicious way that it was brought up and the hurt that it caused my son made me immediatley put my foot down and kick my husband out of the house. Enough was enough. No reason to stay married for the children's sake if your going to go out of your way to screw them up. But now my son is so angry. He's tried so hard to see past his father's faults over the years to find a way to look up to him. Now he is confused and angry and I am sure he feels like he's lost his fishing buddy......my son won't even speak to his dad right now. I hope in time he will forgive him and talk to him. Meanwhile, I am having a hard time getting him to open up to me. It is so obvious that he is a walking time bomb. Do I back off and let him have more time on his own, or do I keep asking him to talk to me? Are you Ok? Are you sure you'r Ok with this? etc...etc...etc..He just keeps telling me that he's just fine and ok, but he's not. I took him to an old therapist that we used to go see.......because of his dad......last night and that seemed to have made things worse.........it took him 30 minutes to open up a little to her and then the session was open.........so there he sat with his 'open can of worms' as they say. I let him know that he could talk to me, but for some reason, he's uncomfortable talking to me in debth about it. What should I do? Any advise?