How to Survive Your Husband's Midlife Crisis: Strategies and Stories from the Midlife Wives Club

This book is from a few years ago and we have not had a review copy. However given the interest in male midlife crises from the wife's perspective, we've been working our way back through all available resources on the subject.

From the publisher:

Guide for women whose husbands have entered a midlife crisis. Written by wives and experts on recognizing the symptoms; coping with the threat of infidelity; handling bad behavior, such as thrill-seeking, financial irresponsibility, or substance abuse; identifying underlying problems; deciding how or if to stick it out; and protecting your kids from the fallout.

Amazon had generally positive reviews though one person felt it came from "too negative" of a perspective. That said, you should never base your actions or rely too much from any single source so this is probably an appropriate piece of your information puzzle.