Right now, detaching will be the most difficult thing you have to learn to do. Its HARD and I wish I could give you simple steps to accomplish this. I can't.
The best thing you can do is work on your GAL. ANYTHING you can do to take your mind of the sitch will help. I just tried to keep myself as busy as possible. Anytime you can be in a environment interacting with other people (that don't know about your sitch), you will be in a place where you aren't actively thinking about it. Do that as much as possible.
Me: 48 y/o W: 47 y/o Together: > 20 yrs BD: Dec '15, then S 2nd BD: Mar '16, then I filed for D April '16: started piecing