I mean I’d say the best way to approach him is directly. You got tested, were clean, and now have issues. It’s possible he’s a carrier and doesn’t know, as some people simply don’t show symptoms. So I’d be careful writing his feelings off for you. You assumed he was tested, maybe he assumed he was clean. You both made some mistakes, hopefully his was unintentional at least.

For now I’d focus on getting the results to see how treatable it is. And if it’s one of the “gotta manage it but it won’t ever go away” STDs well then I’d say your future dating pool is pretty limited and that’s not fair but unfortunately how it is. Good luck OP. Sorry about everything