I would voice my feelings to him, and confront him on this. While he is a good man, you don't want your future children to lose their father before they even graduate high school, much less you lose your husband.
If he can't change his habits, I would not keep putting myself through this. There is a quote, you shouldn't light yourself on fire to keep others warm. If he's spiraling down to hell, you shouldn't let him drag you down like an anchor as well. I would get rid of him if he refuses to change. There is a healthier man out there who is more fit to be yours, but that is only if he can't change.
Keeping him at that point will only cause you much more hurt in the future when his body finally has enough. That's not something you want to go through, it's much harder than just a break up, especially if he gives you children. You don't want to be that one widow who visits a headstone in the cemetery with a little child's handprint on the stone, celebrating his life as a father.