Hi, I am so sorry that you had to read this. I know it must have hurt your feelings so bad. With this said, look back at your relationship with your parents as a young child. I know that at many different times in my childhood I "hated" my parents, especially my mom and she was the one that took care of us for the most part, although they were, and still are, married. I can even remember a journal that I had that I would write how mad I was at my mom when she did something I didnt like. It is normal for children to feel like this against their parents. Now I can totally understand how you would feel hurt that most of these feelings were directed towards you, and that she states that your dad could do so much better. But look at it from this child's eyes, especially if her mom is telling her that it is your fault, and that her mom doesnt like you. The child is just emulating what her mom is saying.
Look at what you do with them, do you think that you are mean to them? Does the dad back you up when you reprimand the children, does the dad do most of the reprimanding or do you? I know just last week my stepson got very upset with me because I told him it was time for dinner, and he wouldnt sit next to me at dinner (he ALWAYS sits next to me) because he was upset with me. Dh even went and told him that this was his rule too, and still step son said he was mad at me. As a child, you have to blame someone for your problems and you are the easiest target. It stinks, believe me I know.
IMO, dont tell the child you read this. This will really upset her, she will feel like you are invading her privacy, and I am sure she will tell her mom who will only fuel this fire. Maybe, you could start telling her more often that you love her, and give her more affection. Let her know that you love her like your own. And that it is ok that mom doesnt like you. Maybe you could have your husband back you up on this also. You know, have dh tell her that he loves you so much, without shoving this down her throat. Good luck!!!