I stayed stuck for five long hellish years because I accepted the blame for all his problems.
I kept telling myself he was a good person inside, that if I just loved him enough, said the right things, did the right things, that he would change.
That kind of thinking almost killed me in the end.
Your AH is not helpless and dependent. He's an adult. He wants you to think that because it keeps you stuck where you are.
Are you attending Alanon? Have you read "Codependent No More?"