Someone suggested the book The Journey from Abandonment to Healing by Susan Anderson; I'm reading it and it is very good.
If Understanding the Midlife Crisis by Peter O'Connor is the owner's guide to the MLCing spouse, then I think Anderson's book should be the owner's guide to the LBS spouse.
I posted this on your other thread, but it's an article about how to work on mindfulness and taking your mind off of your worries:
Me: 44, Wife: 39 M: 17 years T: 20 years Bomb on 08/25/09 1/13/10: MC started 1/28/10, 2/8/10: More bombs 8/28/10: Wife moved out No talk of D, no movement