Surviving infidelity by Subotnik and Harris. Excellent intro and indirectly led me to this site! Should be on all of our shelves.
The relaxation and stress reduction workbook by Davis et al. Good book to skim for your 'issues'. Rec. by my counselor. Didn't read much but I refer to it periodically.
A complaint free world by Bowen. Introduces a challenge to stop complaining and reduce your negativity. Great for pissed off, grieving BS's.
Calming your anxious mind by Brantley and Kabat-zinn. Skimmed initially but will revist. About mindfulness.
Codependent no more and The new codependency by Beattie. Good for spouses who carried most of the weight in the marriage.
When Things Fall Apart by Pema Chodron. Kickass intro to buddhist thinking. Helps you identify the 'middle' and stay away from the 'extremes' especially extreme pain/negative thinking.
Wherever you go, there you are by Kabat-zinn. Great practical guide to calming your inner dialogue and focusing on the moment.
Freedom by Franzen. Recommended by a counselor friend. It's very relevant and about a relationship gone south. I just started it and it is fiction but it is a very good read so far. i can't put it down. I think it would be a comfortable albeit close-to-home read for BS