I'm not sure if you will post again, but I feel very similar to your situation. I have been trying all the things that Tuff Girl said not too....You CANNOT talk him out of drinking. Tears, threats, silence, nothing will work.
I feel the stress you are living right now is far worst than the stress caused by the unknown of leaving him. You can't save him...as everyone here seems to say. Maybe, as I tell you this, I will listen to my own advice. If he wants to do something dangerous, it will happen with you there or with you free. Your own happiness is at stake. Why should his poor life choices ruin your life too. I am always trying to save my boyfriend. This is stupid and doesn't work. 'Let him fall' -maybe he will realize and pick his ownself up. Last weekend my 30 year old boyfriend broke a beer bottle over his head in some (college-like) stunt. His forehead has a huge gash and his stupidity overwhelmes me. I am doing my best to let him go down in his own flames. Good luck!!! Stay tough