Then go dark which is as little contact as possible. Only discuss factual things about kids, set up clear and hard boundaries of interaction. This is whatever works for you, maybe just text messages. Also is it possible to minimize interaction in the same house? How would you deal with a room mate that was sharing your house but you knew nothing about nor liked particularly?
Yes I know this is very hard, this person looks an sounds like someone you knew, loved and shared a life with. But she really is not the same person.
You have to start finding your own footing and it will be very hard until you can separate emotionally and even physically.
