I copy & pasted it, i want everyone to see because it is so on target.

That's very, very, very typical behavior. Rather than change her, the best thing you can do is to read a few books and see professionals talk about her behavior. Then get your DH to read the books (some, like "Stepmonster" and "The Smart Stepmom" can be read in a day), so that he realizes how typical his kid's behavior is. That way, he can see his kid's behavior for what it really is, rather than continually trying to figure out what you did to deserve it. It's a shift in focus.

It's way too easy for everyone to focus their blame on the SM. She's the first to be blamed, and the one who accepts blame the easiest. One of the books says that a relationship between a stepmother and stepchild will mirror the relationship between a father and his kid. If she's secure with him, than you aren't a threat. If their relationship is not good, she sees you as a threat. Her jealousy and insecurity will continue to be present, as she shifts her blame to you for the reason she's doesn't get the attention from him that she thinks she deserves. You could be a pet goat and she'd act the same way.

If your DH puts you down to appease his guilt over not being there for his kid, he's telling her that he feelings are legitimate. They will continue. In fact, her attitude may never change.