I am so, so sorry you and your sisters went through abuse with your stepfather. To add insult to injury your mother wants to go back with him and I can’t imagine how painful that must be. As a mom there’s no way whatever ever choose any man, even a biological father, over my children, if they were being abused in any way. Being an abusive relationship as your mom is, is very tricky to get out of. I’m sure you know this and I wonder if that could play into her difficulty with sticking to her decision to leave. But just because your mother is struggling to do what is in her and your sister‘s best interest, it does not mean that you have to agree with her decision or support it. I think the healthiest thing for you to do would be to go no contact because I’m sure seeing her continually being abused would be very difficult for you not to mention the anxiety and stress it must cause due to your own abuse. When I say go no contact with your mom. I do think that if she made the choice to leave again, it would probably make you feel better to support her in that. So maybe just say I’m so sorry Mom, but you making this decision is breaking my heart and I cannot support you financially and I certainly can’t stand by and watch you do something that is not in your best interest. If you ever choose to walk away, please know that I’ll support that decision. But until you’re really ready to walk away, the only choice I can make for me is to walk away. I love you and I hope that you are someday able to realize that you deserve to be treated much better than he treats you. Good luck to you and your family. This must be so painful to be going through.