Tony has a way of bringing people down when he sees that they are changing for the good. Him tempting chrissy with wine reminded me of when he sabotaged Janice when she was trying to work on her anger.
With that being said I do think that either way Christopher was a ticking time bomb. He betrayed Adrianna. The awful ways he talks about her is to try to justify that he made the right decision giving her up. And the substance abuse is to drown out and numb those feelings.