American marriage is unique, argues Andrew Cherlin ( The Marriage-Go-Round: The State of Marriage and the Family in America Today , 9-10), because American marriage marries individualism and marriage:

“Family life in America comprises both cultural models - marriage and individualism. Each is part of the cultural tool kit . . . that people use in constructing their personal lives. You can use one set of tools today and another tomorrow. You may cite the prestige and material advantages of marriage to justify marrying your live-in girlfriend or boyfriend. Several years later you may use the language of expressive individualism to justify leaving the marriage because it no longer meets your personal needs. Sometime after that you may employ the model of marriage again. Both cultural models are so ingrained that Americans move from one set of tools to another without necessarily realizing it.”

And behind this oscillation are the unique institutions of American law and religion: “The contradictory cultural models of marriage and individualism remain central to American family life in part because religion and law transmit and reinforce both of these models in ways that differ from . . . other Western countries.”