“We love each other and want to be together, and we’ve made the commitment to stay together until death parts us,” Ms. Kanter said.
But although they have been a couple since 2002 and have shared a home since 2004, they are not married. And among older adults, they have a lot of company.
The number of people over 50 who cohabit with an unmarried partner jumped 75 percent from 2007 to 2016, the Pew Research Center reported last month — the highest increase in any age group.
“It was a striking finding,” said Renee Stepler, a Pew research analyst. “We often think of cohabiters as being young.”
Most still are. But the number of cohabiters over age 50 rose to 4 million from 2.3 million over the decade, Ms. Stepler found, and the number over age 65 doubled to about 900,000.
Demographers are paying attention. At the Population Association of America’s annual meeting in Chicago last month, featuring a session on “repartnering” in later life, the panelist Jonathan Vespa of the Census Bureau pointedly offered a presentation entitled, “A Gray Revolution in Living Arrangements.”
The trend partly reflects the sheer size of the baby boom cohort, as well as its rising divorce rate.
So-called gray divorce has roughly doubled among those 50-plus since the 1990s. Divorce leaves two people available for repartnering, of course; losing a spouseleaves one, and these days it tends to strike at older ages.
But attitudes have shifted, too. “People who’ve divorced have a more expansive view of what relationships are like,” said Deborah Carr, the Rutgers University sociologist who served as chairwoman of the Population Association panel.
“The whole idea of marriage as the ideal starts to fade, and personal happiness becomes more important.”
Of course, the boomers pretty much invented widespread premarital cohabitation while in their 20s and 30s — or like to think they did.
“It used to be called shacking up, and it was not approved of,” said Kelly Raley, a sociologist at the University of Texas, Austin, and former editor of The Journal of Marriage and Family. Families and religious groups often condemned living together outside marriage.
But Americans are far more accepting now, she said, and the people turning 60 “are very different from the people who were 60 twenty years ago.”
Karen Kanter, for instance, had divorced twice after long marriages — 38 years, in total — when she met Mr. Tobin on Match.com. “Getting divorced gives you so much to untangle,” she said.
“Our life is good together, so why disturb it? I just don’t see the importance of that piece of paper.”
Mr. Tobin, also divorced after a long marriage, wouldn’t mind marrying his partner — he actually proposed on bended knee once, though he knew Ms. Kanter would say no — but he is also fine with cohabiting.
“The relationship is looser,” he said. “We don’t make demands on each other’s time. She has her life, I have my life, and we have our life together.”
For older people, the advantages and drawbacks can stack up differently than at earlier ages, when such relationships tend to be more unstable. Demographers see most youthful cohabitation as a prelude to marriage or simply a short-term arrangement.
In later life, however, cohabitation — like remarriage — brings companionship and wider social circles, not to mention sexual intimacy, at ages when people might otherwise face isolation. Financially, pooling resources in a single household often improves elders’ economic stability, especially for women, who are at higher risk for poverty.
It also offers certain economic protections. Older adults have more debt than previous generations, Dr. Carr pointed out, including mortgages and children’s college loans. “You become responsible for your legal spouse’s debt, but not for your cohabiting partner’s debt,” she said.