I have no idea if you should leave him, or how doing so might effect your life, but I would like to point out that it is HE, not you, who has signed a death warrant. Unless you are pouring booze down his throat..
I agree with others here, check out the family/friends forum, maybe try out al-anon.
Sometimes addicts do use "guilt" of their partner as a means of keeping their partner there to support their addiction. Just something to consider.
Also, my ex husband divorced me over my issues with addiction and mental illness. He is much happier now, and somehow, lo and behold, I've not only muddled on, but I am clean and sober!
It's possible your husband is more resourceful than either you or he realize.