More than 65 percent of first marriages today are between couples already living together. For millennials, cohabitation is almost a rite of passage. Oliver Hoffmann/iStock hide caption

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Phillip Underwood and Michelle Sheridan and their children, Logan and Lilliana, gather in their living room in Frederick, Md., after a long day of work and school. The couple had delayed marriage, in part for financial reasons. James Clark/NPR hide caption

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Edith Hill, 96, and Eddie Harrison, 95, shown here in their home in Annandale, Va., were married earlier this year. One of Hill's daughters says the marriage was improper and that Hill's estate is now in question. Matthew Barakat/AP hide caption

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Rick and Marianne wash dishes together. She no longer remembers that he is her husband. Andrew Nixon/Capital Public Radio hide caption

itoggle caption Andrew Nixon/Capital Public Radio

John Betar, 102, and his wife Ann, 98, at their home in Fairfield, Conn. They eloped on Nov. 25, 1932. Michelle McLoughlin /Reuters/Landov hide caption

itoggle caption Michelle McLoughlin /Reuters/Landov

A bride and groom exchange rings during a traditional Indian wedding ceremony. Although most marriages in India are still arranged, a growing number of women are taking matters of the heart into their own hands, using social networking clubs and matrimonial websites. iStockphoto.com hide caption

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Having a special someone won't fend off depression if that person doesn't have your back. iStockphoto.com hide caption

itoggle caption iStockphoto.com