Thank you for the support. I never expected so much traffic from a post I made to work through my feelings yesterday.
A few things I have to answer. Pretty random, but anyway.
First, I love my W. I might have described her in very negative terms. But she wasn't always like this. Yes, she didn't discipline sS15, but she was always very caring. And she is very intelligent, beautiful, artistic and can teach D5 a lot of things. She is good at pretty much everything she starts, perhaps w/the exception of relationships. And W's behaviour has changed over the last 1.5 years dramatically. Her own 180s to make HER happy in life. I still see someone not so selfish somewhere in there. And I already did leave for several months and I think now that I made a mistake. So I'm not ready to give up yet and leave again.
Another thing I haven't mentioned, sS15 survived leukemia as a small child, so there is another reason for her 'to be good to him', besides not wanting to repeat 'mistakes from the past'.
Regarding custody for D5 I'm not sure. From what I heard if W fights me it might be difficult for me. Usually the mother is preferred. And currently W would NOT let me take D5, although I'm perfectly capable of taking care for her. And she WOULD miss mommy. I don't want to take her away. It would be a reasonable option for me, but in reality it is currently NOT one.
I don't know if sS15 biol. father would take him right now. That's something W probably needs to find out. If she is going to do ANYTHING at all. She is TALKING about doing something for months. But she is not DOING anything. I gave her suggestions in the past but I can't make her do things.
She also was talking about Boarding school. I'm not sure how to pay for it but it is certainly worth looking into.
Again, thanks for the comments and any further suggestions are appreciated. For now I will just hang in there, make sure that D5 is ok, try to be ok, and let W and sS15 work on their stuff. Oh, and I still will DB my a$$ off. And I will backslide. I will be able to know I tried everything I could and will be able to tell this D5 when she is D20 or D40.