I second the motion of anything by Melody Beattie.
My personal favorite is "Women Who Love Too Much: When You Keep Wishing and Hoping He'd Change" by Robin Norwood.
This book has helped me SO much. My exWSO was not an addict but was passive-aggressive. Like any book (or forum), take what helps and leave the rest. I found about 75-80% applied to me and my situation.
What I found the most helpful was the chapter on how to recover !! Excellent. Step-by-step instructions.
In a nutshell: focus on YOU. YOU can't change anyone else. Put all the energy that you have been throwing away on someone else, on an unhealthy relationship, back into YOU.
Actually kind of reminds me of the 180!
Hope this helps. Bibliotherapy has really helped me. And IC too.