Jack offers good advice - particularly on the NOT moving out. I did. It is now one of the things in life I don't get a Do-Over on.
You may have made some mistakes you would like to take back. We've all had that wish. Don't add moving out to your list. You have done nothing so wrong that you should punish or martyr yourself into giving her and her new friends free run of your home. If you do, expect to see all of your pictures disapear along with pictures of your children. They will be sad to see that they are a reminder to her of her real age. She wants a Do-Over. She is intent of being 17 again. It is not her fault, it is the MLC mind that has taken over.
In response to Any/All comments from your W about separating or moving out ... "I regret that you feel that way and that it has come to this. I understand there could be some financial burdens generated by one of us renting a new place, but that is the nature of ending a M and we must both accept that we could be faced with that. It will be painful, but I will help you move as soon as you find a place that meets your needs. As for the money, we may have to start cutting back, liquidating some things, or borrowing. In comparison to a D, it will be a small order of fries."
As for living with your folks, if she is sure it is such a good idea, move her there.
Jack may be able to go into detail at some other time about helping his MLC W move. His kids were in a better place at home with him than mine were when I left them with their MLC mom - the X. I live back in my home today with a 20+ son who fell into a very dark place during all this. I truly believed I was going to lose him too. After a couple years of struggle, he is slowly doing better and returning to a better world. Her new friends helped her move her clothes, makeup, and a very large check that I won't pay off in a lifetime.
Don't spend time worrying about what might be the worst possible outcome and trying to avoid it. Think instead about what might be your very best possible outcome with or without her, and begin preparing for it yesterday. Who are you? Who will you be?
I know it's a lot of words for about the same thing as what Jack said. I really like his answer and wish I had been strong enough at the time to use it.
