I went through this with my daughter....insisted she wanted to live with dad.....broke my heart, but I let her follow hers.
She never moved. She stayed with me, and in time came to see that she could see him whenever she wanted, and still live at home.
It was hell for about 6 months, but she needs to find out for herself what the realities are.
And it's true that they'll push your buttons because they know they can trust you. All of mine did that.
Be there for her. And let her feel her way for herself. It's the toughest thing I ever did, but my daughter knows she made her own choices, and things are great between us now.
I hope things work out for you two.
-------------------- Anne Marie
----------
Been there, done that, got the t-shirt:)