So - once you list the house, should you be filing? I just hate to see the house sell without you having some kind of legal protection in place. And I'd be worried about him spending his half and leaving you holding the bag for the credit card debts or whatever.
OW is a crazy whack job and I agree with everyone else - your sister should block her on FB. No need for ANY contact, it just gets her wired up. And I have no idea how dangerous she might be.
It's interesting that you had that scary intuition about the possibility of her pushing you from a cliff. That IS weird that they invited you on a hike before you knew about their affair. And she sounds just loony enough. Watch your back.
