Kitty I am right there with you - my AH was sober 1.5 years and has recently started drinking. I have had thoughts of just washing my hands of it all - but as my sponsor has told me - if I get better than the likelihood of him getting better increases and our relationship too. If I give up, then I stand the risk of finding someone just like that. At this point she wants me to focus on myself, because if I don't, I may be destined to continue seeking out people like him. And honestly, he and I have history, and a family, and there is no abuse. He has to find his own way, and I hope that his relapse helps him realize and find sobriety again, but I'm not trying to force him to do anything.
I remember a neuroscience class at school that this thread made me think of, especially lexiecat's post. When the A has no one else to blame, they finally have only one person left to look at. There was a condition we learned of, where people ignore parts of their body. For example they will ignore an arm - they will only dress half of themselves etc. Research showed that a treatment that worked was to ***** the 'ignored' arm with a sharp object. Because they don't identify with that limb, they feel pain and look at the other arm, the functioning one. But they see nothing there that could have caused the pain. Their attention (I guess by the doctor) is turned to the other arm and they see the object causing pain, and through this they are forced to acknowledge the limb. It wasn't so much a physical condition, it was an ATTENTION condition. When all other options were gone, they were forced to turn their attention to what was being previously unacknowledged. Lexie is right - when we are the 'functioning arm' then the person can ignore the real cause. Take the arm away and they are forced to see themselves and fend for themselves.