Is there such a thing as an affair-proof marriage? Is it possible to love more than one person at once? Why do people cheat? Can an affair ever help a marriage? Infidelity is the ultimate betrayal. But does it have to be? Relationship therapist Esther Perel examines why people cheat, and unpacks why affairs are so traumatic; because they threaten our emotional security. In infidelity, she sees something unexpected - an expression of longing and loss. A must-read for anyone who has ever cheated or been cheated on, or who simply wants a new framework for understanding relationships.