I don't get how this child part system works... Do you have control over them or not? Must be really frustrating if not.
Anyway, I'm gonna stick with telling your T about it. Yes, it's her divorce but she was the one bringing it into your sessions. So she may as well help you out with it now.

On the second thought, if all you really need is her telling you it was not your fault can't you manage to soothe yourself without the help of your T?