Hi, I would suggest you really reconsider being engaged or marrying this guy. He's an alcoholic, based on what you tell us, and do you really want to have that type of lifestyle? He wont change until he is ready, nothing you say or do will get him to go to AA until he's darn good and ready, and that may never happen.
You might want to consider moving back with your folks, even tho you probably dont want to, and leave this guy to himself. If he can sober up and stay sober for a long time, then maybe you can reconsider being with him, but I think things will go downhill for you if you stay with him.