Forty percent of newlyweds are previously married or widowed people tying the knot for the second time, a phenomenon driven by an aging society where traditional patterns of marriage have shifted dramatically in recent decades, a new report said.

The report on remarriage, released Friday by the Pew Research Center, also confirmed the long-standing perception that remarried men are far more likely than remarried women to have a spouse at least 10 years younger.

And it captured a sharp disparity in the way men and women view marriage: Most men are eager to marry a second time, while most women say one time was enough.

The findings offer a striking glimpse at the flip side of marriage’s long decline in the United States. With cohabitation on the rise, divorce more common and many people delaying marriage, only 70 percent of adults now say they married at some point in their lives, compared with 85 percent in 1960.

But because of the huge demographic bulge of baby boomers, there are now more people who are divorced or widowed and are once again looking for love inside the bonds of marriage.

“We’re not seeing an outbreak in remarriage fever. We’re seeing an increase in the number of people who are in a position to remarry,” said Andrew J. Cherlin, a sociology professor at Johns Hopkins University. “What’s happened is that the share of the population that’s divorced has risen greatly. In particular, the baby-boomer generation — which experienced more divorce than any generation in history — is now in their 50s and 60s. They’ve lived long enough, and there are now more of them to get remarried.”

Galina Rhoades, a psychology professor at the University of Denver, said the report shows that the aftershocks of the 1960s sexual revolution continue to reverberate through American culture.

“A lot of these trends are related to big shifts we had in the 1960s,” Rhoades said. “That really changed how relationships function.”

The report is based on analysis of the Census Bureau’s newly released 2013 American Community Survey, along with data from the 1960 and 1980 censuses of people who were divorced or widowed at least once. The Pew analysis did not include same-sex-marriage data, which became available for the first time last year and is limited in scope.

Pew’s report said 42 million adults remarried in 2013, up from 22 million in 1980. Among married couples today, 23 percent had been married before compared with 13 percent in 1960. It found that 8 percent of newlyweds in 2013 had been married three times or more. It also found that 20 percent of all marriages in 2013 involved spouses who had both been previously married.

Gretchen Livingston, senior researcher at Pew, said she was surprised that four of 10 new marriages involved people who had been married before.

“I was struck by that number,” she said.

The report also highlighted ways in which views of marriage have diverged along gender and generational lines.

While older Americans are more likely to remarry today than in 1960, younger Americans — ages 25 to 34 — are less likely to remarry, with 43 percent remarrying in 2013 compared with 75 percent in 1960. Among older adults, 50 percent remarried in 2013, up from 34 percent in 1960.

Among previously married or widowed men, 65 percent would remarry or at least are unsure. But only 43 percent of women would walk down the aisle again or consider doing so. Among men, only 30 percent do not want to remarry; among women, the figure is nearly twice that, at 54 percent.

“Older divorced men are used to being cared for by their wives on a daily basis. Older divorced women may not want to do that anymore,” Cherlin said.

The report notes that those attitudes are reflected in the pattern of remarried couples — 64 percent of men have remarried, compared with 52 percent of previously married or widowed women.

“It may be that women feel they have more to lose, essentially, by getting [re]married,” Rhoades said. “I think we are still, unfortunately, in a society where women have less power than men do. And not being married to someone is a more powerful position to be in.

“Maybe they don’t want to feel stuck again. Maybe it feels like there’s some more freedom in that.”

The report noted, however, that this gender gap has shrunk, as men have become more reluctant to remarry than in the past, while women are more likely to do so.

And the report suggested that when men remarry, they are more likely to marry someone younger. About 16 percent of newly remarried couples include a husband who is at least 10 years older than his wife, compared with 4 percent in first marriages.

Cherlin said the data may reflect the law of supply and demand as much as cultural views.

“Men have a more favorable marriage market because they’re allowed and encouraged to marry younger women. Divorced women are less likely to marry a younger man,” Cherlin said.

Said Livingston, a senior researcher at Pew: “I feel like there’s another whole report to be written about that.”