Living together before marriage is becoming more and more common among dating couples. According to the U.S. Census Bureau, more than 3.7 million unmarried opposite-sex partners were living together in 1994. One of the most frequently heard reasons for living together before marriage is that the arrangement is a kind of trial marriage to see if the relationship will last. Critics of premarital cohabitation charge, however, that living together before marriage does not prepare a couple for the reality of marriage. They cite studies that show, in fact, that couples who live together before marriage are 33 to 80 percent more likely to divorce than are couples who do not cohabitate before marriage. Opponents of premarital cohabitation also contend that the longer a couple lives together before marriage the more likely it is that their marriage will end in divorce.

However, some researchers maintain that...