Kind of but your example isn't great. It's in some senses more of a concern with things like HPV + HSV, where there's not a lot of testing options and barrier

Kind of but your example isn't great. It's in some senses more of a concern with things like HPV + HSV, where there's not a lot of testing options and barrier contraception is of much more limited effectiveness. (that said, Gardasil vaccination helps). For most other STIs - either get tested before every new partner or on a reasonably frequent basis, and demand the same from every new partner. HIV prevalence + transmission likelihood is wildly skewed to gay/bi men who are active with men - and if you are one who's actively having new partners you probably ought to also talk with your doctor about PrEP.