Psychologist John Gottman and his wife Julie, also a psychologist, in New York City. Together, are renowned experts on marital stability who run The Gottman Institute, which is devoted to helping couples build and maintain loving, healthy relationships based on scientific studies. They have been studying couples who not only endure, but live happily together for years and years to try and identify what helps those couples last. They have found that more than anything else, a spirit of kindness and generosity guides those couples whose relationships last.