For centuries, marriage functioned as a political, practical, and economical union, depending on your station in life. For the aristocrats, a good marriage secured fortunes and position. For common folk, it meant having enough kids to work a farm. It is only in the last 100 years or so that the idea of a passionate marriage took hold of the popular imagination. Today, most of us are less worried about basic survival and can focus more on what we desire in a union. Usually a healthy, dynamic, secure, relationship that is predictable, but not when it comes to sex, which people want to be anything but staid and predicable. Our guest is Esther Perel, she's based her career on how to unite those conflicting desires. She’s a psychologist, sex therapist and author who specializes in couples and sexuality. Her TED talk (watch it below) on “The Secret to Desire in a Long-term Relationship” has over 2 million views. Her bestselling book is called “Mating in Captivity: Reconciling the Erotic and the Domestic”.