This is so unrealistic. Old people get horny still, just have less stamina and have to take body pain into account. They'd be humping like rabbits every day already if they got their young bodies back.
Thank you for this! This is a beautiful manga.
@Mako992 I believe she's saying not to make their husband jealous of the love his wives share for one another. He would be jealous that his old wife loves his new wife more than she loves him.