Does it really matter if there are a few 'happy' outcomes in other relationships? How do you see your relationship going? How do you feel about having an alcoholic boyfriend? Are you happy with this relationship as it is? You only have the power to change you - and you are the only one who is able to put yourself first.
Have you read Melody Beattie's Co-Dependant No More? Another book I'd recommend is 'Under the Influence' - this helped me see where my STBXAH's drinking was going. He too would manage to 'moderate' his drinking for a time, but then it would get worse than before. For the past few years he couldn't go a single night without a drink. We were together 18 years. I wish I had read up on alcoholism and co dependancy a long time ago - I would have saved myself so much heartache and misery.
It's been a while since you posted - how are YOU doing?