Fantastic post SCOTT.
'That's how he gets away with this - by making the aftermath about how awful he feels, by denying you the right to be angry by threatening that if you do anything about it, it will make him worse.'
Look back at '"this is making me feel worse, I need to feel better" whenever I scream at him, pack his stuff try to throw him out etc.'
You are being silenced here, Soooo. He is telling you everything you need to know about him, and where you stand in all of this, right there.
And Maryz 'In my opinion addicts only stop using when they find something that they are afraid of more than they are afraid of losing the drug/alcohol. If you walk away from him now he is left with a very simple choice - lose you or give up using. It will be his choice and you have to let him make it.
Please start talking to people in real life. Give nar-anon a ring at least .'
You have to be prepared for the blow to your self esteem that would come with the either/or choice here that you need to give him. Right now he is turning it into a grey blur with his 'promises' and his 'remorse' (aren't words cheap?), but in fact it has always been a very black and white situation -- by doing what he does he is choosing the cocaine over you every time.
Please talk to your brother whom you mentioned earlier. Keeping it from people in RL means you still believe you have some control over your H. It also means you fear the feeling of humiliation that comes from having others know the conditions under which you live -- but that means actually that those conditions are not tolerable. When you try to gut it out in an intolerable situation it is because you need to feel in control of your circumstances and are not willing to accept how little control you really have.
You have a little bit if an investment in the situation here (co-dependency) -- you must divest yourself. Everyone has a bit of that. No-one is an island. But he is taking you further and further from the normal range every day. He is thinking only about himself, and you are thinking only of him. The balance is completely out of whack.
If he has talked about suicide in the past, you really need to step right back from him. He is spinning a web for you with that kind of talk. That sort of shit is actually a tantrum, a grown-up form of tantrum. (though completely immature) You do not have control over this man and you do not have any responsibility for what another adult chooses.
If he starts up with the suicide talk today, call the police and tell them his location if you have it. They will find him and take him for a MH assessment.
There will come a time, if you don't start the tough love, when you will fervently wish he would commit suicide and put you both out of his misery.
He will be very angry with you when you make him face the music. He will bitterly resent being forced to grow up. He will try to blame you for everything that has ever gone wrong in his life, and accuse you of all sorts of manipulation, moving he goalposts, changing your mind and not loving him unconditionally. You will be called cold and cruel and all sorts of crude things. That means you are taking the right tack.