Agree with all of the above. Anger is usually a signal that something is wrong. And even though the alcoholic is wrong, so are you (not in a moral sense, but in a practical sense). You are angry because you are expecting something he is incapable of delivering.
So what do you do about it? A good place to start is to quit expecting anything different and, as mentioned above, start taking care of yourself. That may eventually lead to your conviction that you deserve not to live this way, and to take steps to end the relationship. Or it may lead you to be sufficiently satisfied with your life (because you are meeting your own needs) that you can peacefully co-exist with the alcoholic. Your choice.
Detachment lets you get to the place where you can see that you DO have options. It's feeling trapped that makes everything worse.
You have the keys to your life. Get into the driver's seat.