Tiger this might not be the right thing to say but I'm going to say it anyway. Your contradicting yourself in one sentence you say you've made the resolve to leave in the next your asking me how could I leave?
I said the same things myself a million times and packed my bags and never left another hundred times until one day I finally walked out the door.
Yes when he's not using times are great and he is the love of my life, but can I have a life never knowing when the other shoe is going to drop? NO
I could never make plans to invite anyone over my house because I never knew what that day would bring. & I could never go out when people invited me because they would ask where he is and I'd have to lie. What was I suppose to say he's home smoking crack.
I cried a million tears over this, but I know this is not the way I want to live my life & I know I want children someday and I would never bring them into a life like this.