Your family of origin dynamics, also, sounds familiar for me. It took me the longest to pin point both parents, as I couldn't quite understand dad's personality due to a decade long separation between him and myself. And had to recognize my mom's as more style than disorder. A matyr, for sure, how often did I ever hear other's say, '**** you're a saint. You should be sainted, etc'

I noticed you mentioned a book, I haven't read. 'When I say No, I feel guilty. ', if anything may add that to my wishlist. Which i tend to conquer. ..
I hope the demonination reference isn't too troubling, but one book I really seemed to click with, reading, was no more christian nice girl. It was a couple years ago, it definitely helped me.
I agree about how therapy itself not really getting to the heart of these types of affinities. Probably just not enough hours in the day. Plus, I find it's just a trait that one has to really, really want to adjust.
Not book related, but something else, from another support group, years back, that stood out. Reflect and ask, what's my own personal motivation? Why am I saying yes?