I told them both that they are siblings and need to work this out. I told my W that she has made it clear that she doesn't want my opinion about anything else and asked why is this different. Her response was golden...she said that I have always been her buffer between her and them. Hasn't she fired me from that role?
Why did you even respond to this note to any of them? She was just copying you on it, right (for Lord only knows what reason)? I wouldnt go around "telling people what they have to do." It isnt your fight anymore.