He hid a possible std from me?

Today, we were at my boyfriends sister house. She was asking a (dumb, not important to the story) favor from him and when he started to refuse, she went on a rant that she had to once listen to him rant on in public about how he had red bumps on his dick that he believed were from his ex (the one directly before me) so he should do her favor in return. I later questioned this and found out it was during the beginning of our relationship. We had sex the first time we met and quite a few times before we actually agreed to date. He never once mentioned he thought he had a std. He claimed he just used condoms to prevent possibly giving me anything but yet we did things orally also without a condom so im confused on that logic. He was later tested (he claimed it was just because he had recently found out his ex cheated on him with a few guys) and found out to have nothing. The bumps were possibly from chronic masturbation from the time period between her and i he believes. This was a year ago but I still feel almost betrayed he had sex with me when he thought he had something? I’m not sure how I should feel about this. Should I just forgive it because it was a year ago? How do I go about this? It was when we first were together and neither of us thought we would date or for this long. But it’s kinda messed up he lied to me about that, right?