I, personally, don't think that the separation is her way of showing withdrawal. She's still seeing all of her new friends and the separation is her way of being able to do the things she wants to do w/o you watching and questioning her every move. She looks to you as an authority figure (father) right now and she doesn't want "daddy" to know what all she's doing.
Withdrawal is when they show no interest/motivation in anything. They just want to be left alone to think and sit around looking at four walls. You are trying to mix apples and oranges here with withdrawal and separation from the relationship and you.
You have to start thinking of her as being someone different. Her interests are different and her personality is going to be different. The person you are saying that you can't see her being holed up somewhere is the person that you once knew. The person you are dealing with now is a different person. Think of her as being the mirror image/opposite of the wife you know and love.
No one is telling you to shake the feeling that you can still be great. You can still have hope that things will work out, but you've got to start thinking a bit differently in how she is today, not what she was like two years ago. You have to find a way to accept her for who she is today. Your expectation level w/her needs to be backed down to zero because if you don't do this, you are going to be disappointed when she doesn't do or say what you think her responses/actions should be.
Yes, I did recommend Solo Partner. It's an excellent book that I read many years ago and still recommend it today.
You will that I will continue to circle back around and tell you to keep the focus on you. I know it's difficult, but you need to do this. As the old saying goes "a watched pot never boils". Leave her alone, allow her to do what she needs to do to heal. Keep your eyes forward and continue taking one step at a time forward.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.
