I don't know if you are overreacting, but it sounds like you are giving her exactly what she is looking for. My response to all of that would be... pause to remain calm.... "now why would you say that?" or "why would you ask me that?"
Don't expect any compassion from her regarding the accident. In fact, don't expect anything from her.
I need to say that her taking the kids to be around this person, in my opinion, is absolutely unacceptable. This is where I would draw the line. My wife's BF lives 300 miles away, and I believe that only the four-year-old has seen him through a car window. But I will not permit them to be around him until D is final.
