Grace,
I know how hard it is to walk away from family. They are family afterall. but when there are toxic people in your life and you know it; it is time to put some distance bwtween you. At least until you can be around them and not feel hurt or angered by them. What I mean is.....well, pretty much the same to what has already been stated above, is that you cannot change these people. You know how they are and how they make you feel. The only thing that you can change is how you allow it to affect YOU.
First you have to learn to accept and love yourself. When you have your own self confidence and self-esteem issues, it greatly effects how you handle other situations in life. I understand about how if feels to be having to move back in with "Mom" after you ahve been out on your own and have had trouble... I am having to do the same here. I am trying to get out away from the relationship I have been in and on my own, but can't because of money. I am having to share a place with my mom for a short time to get on my feet and I don't like it. My mom and I don't really belong living together.....not good, but rents here are high and I am too established here to move away from this city. What I plan on is doing something to move me up in income in hopes that will secure my future for me and my daughter for me to go it alone within a couple of years.
Anyway, I guess what I am saying is .... good idea to move away from these people with your daughter, and then make a plan for yourself to move towards your own future. Instead of focusing on their problems with you and yours with them, focus on YOU. Take care of you as if they were not even there. Detachment, to me, is just going about living your own life, maybe popping in and seeing what's up with them, but not staying in it when the poision is still flowing, and go on about your day. You do have options........you just need the strength to use them.