Leave D in God's hands. Mine moved in with W and OM after a year with me and it was extremely difficult not to fight it. I left her in the Lord's hands and took the higher road.
Even though my W does not go to church, I continued taking my D15. During one service a little over a year ago, out of the blue the Spirit connected to her heart and she has been on fire ever since. She now won't miss a service or youth meeting, is calling me to make sure I'm picking her up to go, etc. She even volunteered for and is helping to run a Bible study for young kids in a local neighborhood.
I could have never scripted this. Anyone on the outside would have advised me to fight to keep her out of that environment. What would the darkness in that place do to her soul? But God had different plans. She has at times wondered about moving back in with me because she no longer likes the environment she is in, but I have encouraged her to seek the Lord on it as she is now the only real glimmer of light in that darkened household. She has chosen to remain there for now. I still worry about her, but Christ in her life continues to grow her faith and I am confident He will carry her through.
Commit your D in His hands, always be available whenever she needs you, and take her out and be the example of how a man should treat a woman. You will be the date she compares all others to :).
I just finished a phenomenal book, "How We Love" . I highly recommend it to all.
