I'm not sure what you're asking here? I will say that from what you discribe, you need help with your picker. I have to ask why you would stay any length of time with someone who has all those past issues and isn't actively in councelling to help her to get past, well, her past?
You know she "is lost, she is damaged." Do her and yourself a favour and tell her that you have come to the conclusion that you are not good for one another and that you will not be returning any more of her attempts at contact, that you hope that she gets the professional help that she needs to be able to leave her past behind and that you will be doing the same to help you with your own issues. (lack of self-love, fear of being abandoned and lack of confidence in yourself).
I'm glad you feel it would be in your own worse interests to continue on with her. Now all you have to do is tell her you won't be answering anymore, that you are blocking and deleting her and then stick to that conviction.
You are not responsible for her. The only thing you owe her is your honesty. Stop your self-hatred and be proud that you are emotionally healthy enough to realize that you need cleanse her from your life.
To add:
She was pregnant to me and we had a miscarriage which was awful because we fell out before it happened and she kept me away whilst the problems were happening.
Thank your higher power that this happened. The last thing you need is to be tied to her in some way due to a child. I feel sorry for her other three? having to be brought up with her particular kind of mental "ism."
Be strong... You've done the right thing. Now just make it final by going ZERO contact with her.
“The willingness to accept responsibility for one’s own life is the source from which self-respect springs.” ~Joan Didion