When Audrey Davison met someone special at her nursing home, she wanted to love her man.

Her nurses and aides at the Hebrew Home at Riverdale did not try to stop her. On the contrary, she was allowed to stay over in her boyfriend’s room with the door shut under the Bronx home’s stated “sexual expression policy.” One aide even made the couple a “Do Not Disturb” sign to hang outside.

“I enjoyed it and he was a very good lover,” Ms. Davison, 85, said. “That was part of how close we were: physically touching and kissing.”

Ms. Davison is among a number of older Americans who are having intimate relationships well into their 70s and 80s, helped in some cases by Viagra and more tolerant societal attitudes toward sex outside marriage. These aging lovers have challenged traditional notions of growing old and, in some cases, raised logistical and legal issues for their families, caretakers and the institutions they call home.