Originally Posted by
sesh 
I'm the only chance he has to get back on track, to become the person he used to be. If I give up on him he has nothing, he is completely lost...
Please don't take this the wrong way, but you are not that powerful. He will do whatever he will do with or without you.
In order to think about boundaries, you have to think about yourself--the only person you have control over. Boundaries are not rules to make him behave. They are protections for you regardless of how he behaves. How about this for a start? You don't discuss his drinking or drug use with him any more since you know he lies about it. That's a boundary. Since every boundary needs a consequence, you could leave the room if he starts trying to discuss it/lie about it with you. I believe it helps to start with small ones and work your way up to the big ones. Can you think of any others?
L