Last couple standing : a novel

"The Core Four have been friends since college: four men, four women, four couples. They got married around the same time, had kids around the same time, and now, fifteen years later, they've started getting divorced around the same time, too. With three of the Core Four unions crumbling to dust around them, Jessica and Mitch Butler take a long, hard look at their own marriage. Can it be saved? Or is divorce, like some fortysomething zombie virus...