What should I do? Please help me 😔

So, I’ve been with my fiancé for 6 years. I don’t think he would ever cheat. We also have 2 children together.

But lately I’ve noticed that, when I’ve been going down on him, he has a few white spots/pimple like spots on the head of his penis. I know I haven’t cheated or anything, and I know I’m clean, because I was tested right after we got together.

I’ve been trying to search STD’s and stuff, but I’m just not sure on how to bring it up to him?

Should I go behind his back and get tested - and if it comes back negative, act like nothings happened?

- should I ask him, and see what he says? Maybe ask him to get tested?

- or should I just leave and see how the spots on his penis go? See if they get more red or more of them?

Please help me. 😔