I attended a Christmas party with my (separated) AH. He did not drink. Afterward, he grumbled "Yeah, your two friends were really keeping an eye on me and the alcohol." This was funny because neither of my friends even knew we were separated, or that he was an alcoholic. They weren't 'watching' him at all. It was all in his mind.
My best answers to the blame game are vague, things like "Oh, is that so?" or "It's your life, your choices." And then let it go. What will be, will be.