Staying there for the kids is an understandable choice. I'm glad you put them first. Maybe you need to stop saying sweet things to her that she doesn't respond to anyway. Instead, try telling her that she is failing in her family duties. I doubt that will change her. But it might get her thinking a bit.

Just cause she had a lousy childhood is no reason for her to do not want better for her own kids. Try expecting something of her. Start small. State an expectation, and don't be too pleasant if she makes no move to meet it.