Please tell your D over and over that this has NOTHING to do with her. I know you said she has had some behavior struggles lately (as normal kids do), and I can see her thinking this has something to do with her. Also, kids are going to first wonder how this will affect them. Let her ask the questions, but prepared with the answers you will give regarding where she will sleep, what things she will have, what if she wants a friend over, what about holidays, what about if she wants to do things with BOTH of you, what if she forgets something at either house, can she call you, can she go to whatever house she wants whenever she wants, etc. I'm so sorry.....I can only imagine how horrible you feel.
One day at a time. Pray. Do the right thing, and put everything in God's hands.
You will have the same amount of time with your daughter as your wife, correct? Make sure you do.