Stephanie Coontz, teacher and author of The Way We Never Were and Marriage, A History, is director of research and public education for the Council on Contemporary Families. In this interview with Omega, she speaks about the evolution of marriage and changing gender roles.Omega: You say marriage has changed more in the past 30 years than in the past 3,000 years. You've said that the very traits that make marriage in our contemporary society more rewarding have also made it less stable. How so?