How to Be Good by Nicholas Hornsby. From Amazon: "Katie Carr is a good person. She recycles. She's against racism. She's a good doctor, a good mom, a good wife...well, maybe not that last one, considering she's having an affair and has just requested a divorce via cell phone. But who could blame her? For years her husband's been selfish, sarcastic, and underemployed. But now David's changed. He's become a good person, too—really good. He's found a spiritual leader. He has become kind, soft-spoken, and earnest. He's even got a homeless kid set up in the spare room. Katie isn't sure if this is a deeply-felt conversion, a brain tumor—or David's most brilliantly vicious manipulation yet. Because she's finding it more and more difficult to live with David - and with herself."
