Longtime lurker here -- haven't really needed to post because I have had little to no interaction with his kids in the year or so we have been legitimately together.

Backing it up -- we met before our respective marriages ended, but he swears he had told her theirs was over before we met. I am not at all sure this is true. In fact, a good friend of his recently told me that much of what my BF told me was likely not true (this was in context of discussing how angry his kids are).