There's some really good posts here of women working their hearts and minds through this sort of relationship. It takes a while.
You might find Codependent No More helpful. It is by Melody Beattie. She was a former addict and here book on codependency helped me a lot. HoneyPig posts from her daily reader in the next section above every day. It is titled Language of Letting Go.
Sometimes I had to make decisions on what was peaceful. Not what was easy or a habit or what I thought 'love' required me to do. Because my idea of love was more about velcro than love.