Forget that old adage, first comes love, then comes marriage. These days, it's more like, first comes college, a good job, maybe a house and a savings account—and then we can talk about marriage.
As a battle rages over the rights of gay and lesbian couples to get married, experts say the share of heterosexual Americans who are married has fallen dramatically compared to decades past. What's more, the demographics of who is walking down the aisle also have shifted substantially.
In recent years, people with a college degree have become more likely to get—and stay—married than their less educated counterparts, and those who stay married also tend to be much wealthier than unmarried adults.
"Some people have talked about marriage as a luxury good," said Susan Brown, a sociology professor at Bowling Green State University and co-director of the National Center for Family and Marriage Research.
That's a stark switch from decades past, especially for women, according to the research center's analysis of government data on women's marriage patterns by education.
Back in the 1940s, college-educated women were the least likely to be married. The opposite is true now. As of 2011, around 60 percent of women with a college degrees were married, compared with less than 50 percent of those with a high school degree or below, the analysis found.
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"What we're seeing with marriage trends today mirrors what's happening in our broader economy, where we're seeing diverging fortunes for those at the upper and lower end of the spectrum, with rising inequality," Brown said.
Some experts argue that marriage itself is contributing to rising inequality, because people who are highly educated—and therefore have higher income potential—are more likely to choose each other as spouses.
That's making it less likely that marriage itself will move someone up the economic ladder, and increasing the chances that two low- or high-income people will couple up and share their economic struggles, or fortunes.
"The doctor used to marry the nurse. Today, the doctor marries the doctor," said Bradford Wilcox, director of the National Marriage Project at the University of Virginia, which has documented the rapid decline of marriage among people with just a high school degree.
There are lots of theories for why people are increasingly choosing spouses with similar educational backgrounds—or feeling like they aren't in a financial position to choose marriage at all.
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"We're setting a higher bar for marriage today," Wilcox said. "That bar is not easily met for working class and poor women and men."