I struggled on and off for a long time but Generally I am at a point now where i feel so sorry for my mum. How hard it must be to live in such a way. The only way I could accept it was to have empathy. Mind you this is my first pregnancy and I've struggled with my emotions and it's been hard. I start to doubt my myself and question myself. I'm just lucky that my dp understands because she has seen my mum in action.
In your dp's situation I would say to try and learn to take it with a pinch of salt. Don't wrack your brain trying to figure her out, just have faith in yourself and your decisions.