When I spoke with the kids' IC and my IC about these kinds of issues, they both told me the only thing I can do is remind them that they can talk to me whenever they are in an uncomfortable position, or if they don't feel safe. It would be the same advice, even if we were still together. That keeps the lines of communication open so they feel safe to share.
I've read on some other threads that some kids keep a journal with one or both parents. They write, and then the parent can respond in writing. It makes it easier for some kids to share. And if your kids get upset by something x did, you have it in their writing for him to consider, instead of coming from you (since they think we are the cause of any and all problems).
Hug your babies when they are with you, and remember the foundation that you are giving them, which will help them weather these changes.
