A member here has recommended
The Feeling Good Handbook by Dr. David Burns. It's a book about CBT (cognitive behavioral therapy). There's evidence that you can get some benefit from learning CBT techniques on your own.
The links in my signature also have some info about treatment methods, including self-help methods.
There may be some books about abusive relationships that could be helpful.
www.hotpeachpages.net has some articles about abusive relationships, and I think they list some books too.