Everyone ought to mind their own private/personal business.
I have an older friend who was originally from Europe. Out of the clear she said. You know we Europeans don’t have the sexual hang ups you Americans have. If we are ill or for someone reason cannot be with our husband we want his needs supplied Seeing another woman was never a big deal to me. I knew he loved and cared for me . So let their sex life or lack of sex life be between them. It’s their relationship.