I too need to have that conversation. I am truly in the same boat as you. My AH has an 18 pack per day, every day, and has for the past 17 years that I know of. Part of me now wants to know "why isn't he deathly ill?". But it is starting to take a toll on him, he's becoming more and more paranoid, big belly, hands shake, etc...
I have known I need to have "the conversation" for about a year now, but when my MOM brought it up to me yesterday, I could have died right there!!
I do know one thing after talking with my Mom, today is the day I start preparation work that will lead up to that conversation. I am guessing that the convo will not go well and I will need to be prepared to either leaving or him leaving. I am interested in other's thoughts as well.
Good luck to you!
Jen