The Silent Wife by A.S.A. Harrison
In this debut - and final - novel, the author explores a rocky marriage between a part-time psycho therapist and her entrepreneur building-renovator husband. As a licensed therapist she feels pretty sane and together, and her philandering husband seems basically worthless. We learn early on that she decides to do something very bad, and the story fleshes that out for us. Will she get away with it?