The study found that cohabitation among adults in that age range has more than doubled in the past decade.
The number of unmarried adults over 50 living together jumped from 1.2 million in 2000 to 2.75 million in 2010, a major news channel reported.
The research is based on data from the 1998-2006 Health and Retirement Study and the 2000 and 2010 Current Population Survey.
“Similar to their younger counterparts, older Americans are embracing cohabitation in record numbers,” lead researcher Susan Brown, who is co-director of the National Center for Family and Marriage Research at Bowling Green State University, said.
While the trend mirrors an embrace of cohabitation by younger generations, older couples living together tend to stay together longer than their younger counterparts, the study found.
Couples who were living together when the study began, had been together for an average of eight years.
Over the next eight years, just 18 percent of these couples separated and only 12 percent got married, the researchers said.
As previous studies have suggested, the new research indicates that cohabitation may provide many of the benefits of marriage without some potential burdens, such as the mixing of financial assets.
“Older adults desire an intimate partnership, but without the legal constraints marriage entails,” Brown said in a statement from Bowling Green.
The researchers also found that women are especially hesitant to tie the knot later in life because of the perceived loss of freedom and caregiving strains marriage may involve.
Demographically, most older people living with their partner are divorced, followed by those who have been widowed and then those who never married.
The study is published in the Journal of Marriage and Family.