if you are worried, then get yourself tested and don't say a thing to your h.
I KNOW people will disagree but some of that is ignorance and some of it is punitive on their part b/c they're into shaming their spouse or making the OW look like a possible whore, AND some of them, Like Bond, really believe in it and I get that....but
Nothing "punitive" or "shaming" at all, 25 -- just a healthy concern for the distasteful reality of infidelity. Sadly, Nb's husband -- if he's sexually active with OW -- is exposing himself to every partner the OW has ever had, and she's not exactly a member of a low-risk group, if you kwim.