Am I seeking approval or is it compassion? Help with MIL?

Something similar to what's motivating your husband, I imagine: despite the wrongs she's committed, she did enough right to help make the guy you love into who he is today, and you'd like to make your peace with her before it's too late if it's at all possible. I don't think there's anything wrong or odd about that, but I do think you need to stop hiding in the background and secretly patting yourself on the back for being the bigger person. She's made an overture in the form of wanting to talk to you. I'd take her up on it and reach out directly.