Why do happily married couples cheat? Why does the modern egalitarian approach to marriage quash desire? Are the heightened expectations we bring to modern love combined with our pursuit of happiness directly related to infidelity? In this episode, author and couples therapist Esther Perel tackles the topic of infidelity. Perel is recognized as one of the most insightful and provocative voices on personal and romantic relationships and the complex science behind human interaction. She wrote the bestseller "Mating in Captivity" and is a consultant for the Showtime television series The Affair. Perel is interviewed by Hanna Rosin, co-host of NPR’s Invisibilia.