Her moving out, legally, may not be a bad thing. When you meet with your L, make sure you ask him about your state's "abandonment" law, and his interpretation as it relates to your custody.
My wife was very close to doing this at one point during her affair, looking at apts., etc., and my attorney told me it would be VERY good for my request of full custody of our boys if she had gone ahead with it. Told me to make sure I didn't ENCOURAGE her, but that I needn't DIScourage her, either.