Another wrote: “It got me thinking of ALL the sexual bereavement there is, through being single, through divorce, through disinterest and through what I am experiencing, through prostatectomy. It is not talked about.”

Prior research has “documented that physicians/counselors are generally uncomfortable discussing sex with older women and men,” the researchers noted. “As a result, such discussions either never happen or happen awkwardly.” Even best-selling memoirs about the death of a spouse, like Joan Didion’s “The Year of Magical Thinking,” fail to discuss the loss of sexual intimacy, Dr. Radosh said.

Rather than studying widows, she and Ms. Simkin chose to question a sampling of 104 currently partnered women age 55 and older, lest their research add to the distress of bereaved women by raising a “double taboo of death and sex.”

They cited a sarcastic posting from a woman who said she was not a good widow because “a good widow does not crave sex. She certainly doesn’t talk about it…. Apparently, I stink at being a good widow.”

The majority of survey participants said they were currently sexually active, with 86 percent stating that they “enjoyed sex,” the researchers reported. Nearly three in four of the women thought they would miss sex if their partner died, and many said they would want to talk about sex with friends after the death. However, “76 percent said they would want friends to initiate that discussion with them,” rather than bringing it up themselves.

Yet, the researchers found, “even women who said they were comfortable talking about sex reported that it would not occur to them to initiate a discussion about sex if a friend’s partner died.” The older the widowed person, the less likely a friend would be willing to raise the subject of sex. While half of respondents thought they would bring it up with a widowed friend age 40 to 49, only 26 percent would think to discuss it with someone 70 to 79 and only 14 percent if the friend was 80 or older.

But even among young widows, the topic is usually not addressed, said Carole Brody Fleet of Lake Forest, Calif., the author of “Happily Even After” who was widowed at age 40. In an interview she said, “No one brought up my sexuality.” Ms. Fleet, who conducts workshops for widowed people, is forthright in bringing up sex with attendees, some of whom may think they are “terrible people” for even considering it.