You have been putting up with this for a long time. If it was your son who told you she was coming I would just leave it at that. If she doesnt let you know herself she is coming act as though nothing is happening. If she turns up dont answer the door. Returning mail was a good one. Keep your distance with no contact is my thoughts. That way she might eventually get the message. Id do the same with other family members too. I think it is great that your hubby is on your team too.