I have been in the position your eldesr daughter is in. It is the most painful experience in the world. Having a dad who did love me in no way, at all, compensated for not having a mom who loved me and watching my sister get treated with love while I was not. i got straight As, I had tons of accomplishments, friends, was considered pretty by everyone else, etc--- but I still felt worthless and unloveable. Going home at the end of the day to a house where just one person did not love me--- was excruciating. No amount of love from my dad, teachers, grandparents, etc could make up for having a mom who hatedme. It was the one, single most defining aspect of my life--- and still is now that I'm 30 years old. I'm a successful and well adjusted adult--- and yet I'm in therapy as an adult to process the emotional neglect and abuse I suffered as a child. Children who grow up like me and like your daughter have an empty "hole" that can never be filled. You cannot get a mother's love anywhere else. If it doesn't happen in childhood, the child WILL be damaged. Children who grow up in single parent families are far better off than children who grow up in two parent families where one parent is emotionally abusive and neglectful. The problem is not that the "missing" parent is absent--- the harm is caused by watching a parent hate you, shirk away from you, etc--- while giving that love to your sibling. It tells you that you are not good enough, but your sister is. I'm the one with the degrees and accomplishments (and no criminal record)-- but I still feel inside that my sister is "better" because she was loved and I was not. I will never feel differently, no matter how much time passes, because 18 years of growing up feeling unloveable changed who you are. Hearing your story fills me with so much empathy and care for your daughter, I wish I could give her a hug! If she is already feeling that pain at 8-- I can't imagine how she would feel at 18 if nothing changes. I really hope that you can get the help you need and make the decision to change. As a parent, it's about realizing that your children's needs come before your own. Her needs have to outweigh your personal discomfort.