In long-term relationships, we often expect our beloved to be both best friend and erotic partner. But as Esther Perel argues, good and committed sex draws on two conflicting needs: our need for security and our need for surprise. So how do you sustain desire? With wit and eloquence, Perel lets us in on the mystery of erotic intelligence. TEDTalks is a daily video podcast of the best talks and performances from the TED Conference, where the world's leading thinkers and doers give the talk of their lives in 18 minutes (or less). Look for talks on Technology, Entertainment and Design -- plus science, business, global issues, the arts and much more. Find closed captions and translated subtitles in many languages at http://www.ted.com/translate Follow TED news on Twitter: http://www.twitter.com/tednews Like TED on Facebook: https://www.facebook.com/TED Subscribe to our channel: http://www.youtube.com/user/TEDtalksDirector