Hi,
im glad you put this post up, ive just put a similar one up myself, about my ABF.. i get confused by the same things that you do... he is soo great for a couple of weeks, then it slips again. im in that situation right now.. he had to get a train home and seems he has been unable to do this without getting drunk.
i understand your confusion, i struggle with it myself. im sorry im not of any help but i just wanted you to know that youre not on youre own.