Marital history is something that's every bit as important in choosing a mate as age, education, religion, and race

You've been married before. Your mate hasn't. According to a University of Michigan study, this kind of mixed marriage is becoming more common even though potential partners in the modern mating game continue to gravitate to others with similar marital histories.

"Marital history is something that's every bit as important in choosing a mate as age, education, religion, and race," said Hiromi Ono, a sociologist at the U-M Institute for Social Research (ISR), the world's largest academic survey and research organization. Her article on the tendency to marry someone with a similar marital history—"marital history homogamy"—is forthcoming in Social Science Research journal.

Ono calls remarriages, including mixed-history unions, "leaky" marriages because emotional and financial resources often drain out of the current relationship to help support and maintain ties to children and ex-spouses. Sometimes, she notes, remarried spouses "plug" the leaks by cutting ties to former spouses and ignoring commitments to children. But sometimes the leaks are so large the new marriage eventually sinks.

For her study, Ono analyzed data on non-Hispanic whites from the ISR Panel Study of Income Dynamics, a nationally representative longitudinal study of nearly 8,000 U.S. families, conducted since 1968 and funded primarily by the National Science Foundation. Her analysis was supported by the ISR Center for the Ethnography of Everyday Life, funded by the Alfred P. Sloan Foundation.

"With people marrying later these days, there are more single, never-married adults than ever in the marriage market," she said. But even though intermarriage between the divorced and the never married has been increasing, it's still relatively rare.

In 2002, there were about three never-married adults for every divorced adult in the U.S. In 1998, the year Ono analyzed in her study, there were about four never-married adults for every divorced adult.

In her analysis, Ono controlled for age and education as well as the number of adults who had never been married compared to the number who were divorced, and found that marital history still seemed to have an effect on mate choice, particularly for women who had children from a previous marriage. Only about half of divorced adults were remarried to spouses for whom this was a first marriage.

"Divorced women are more likely than divorced men to maintain ties to children and in-laws," Ono said. "Divorced men are more likely than divorced women to marry someone who has never been married before, maybe because they're less likely to have ties to previous partners."

Ties to former spouses, in-laws and others associated with previous marriages tend to cause problems in current marriages, Ono said. "Some divorced people have little or no investment in their former marriage," she said. "Maybe they didn't have children together, or they didn't own a home or work together in a family business, for example. But others have heavy investments in the former marriage, and in these cases, especially for women who tend to be the custodial parents after a divorce, the ties, or "baggage," of a former marriage are likely to be strong and heavy.

"Anyone married to a divorced partner knows how tough it is to maintain a harmonious relationship in the face of constant reminders that your partner once vowed to love someone else until 'death do us part.' When you're single, the norm is to cut off all contact with former partners. But the norms are very different for divorced partners. There are also legal reasons for divorced parents to give money and other support to families formed in an earlier relationship."

The consequences of leaky marriages for children in remarriages can be substantial, Ono said. "Kids in remarriages, even biological children of the re-married parents, tend not to do as well in terms of educational attainment and achievement as kids in first marriages," she said. "One of the reasons may be that even though the income of the re-married family is, say, $80,000 a year, after you take away support to children from a previous family and alimony to an ex-spouse, the new family's real income may only be $40,000 to $50,000 a year."