Kristen Calloway knows she should be grateful for everything she has: a stable marriage, a decent job, and a daughter to be proud of. But she is also a middle-aged, middle-class woman with a raging libido. And it won't shut up. She attends a school reunion and an old friend reveals that she uses an online agency to arrange casual sex. It's not long before Kristen signs up. Enter Zac: young, handsome and thrilling in bed. Like Kristen, he has no desire to end his marriage and for a while, she seems to have it all. As the affair snowballs, juggling work, family and this new sexual freedom becomes increasingly tricky, but she is reluctant to give it up. Until Zac starts to want more. A lot more. Rapidly things start to spiral out of control, with fatal consequences. Sexually charged, shocking and relatable, Infidelity is a profound exploration of marriage, motherhood and sexuality.