I think the answer to this question is right in front of us, we just have trouble accepting it. The alcoholic is addicted to the alcohol. They cannot put it down until they seek recovery. I'm sure you are very important to him, but he is an addict, and as long as the addiction is active, he will choose the drug over you, because he is physically dependent on it.
Since I am not an addict, I can't begin to understand why they can't just simply stop drinking. Why on earth would I risk losing my partner, my children, my job, my friends, or even my very life? For me it is simple... don't drink. But I believe in the brain of the alcoholic, it is much more complex.
Try not to take this personally. You just happen to be a casualty of this war. You understand that you can't control this, so you are doing what you have to do for yourself. With everything (and everyone) he loses, he will be one step closer to finding recovery some day. I am so sorry that you are hurting.