I need advice...

So I get cold sores once in a great while and I understand how cold sores work. I’ve been seeing this guys and we started finally kissing but I’ve very briefly went over that I do get cold sores, and Idk if he 100% understands what cold sores are or how they work. And i don’t want him to think I’m dirty :(, I’m scared that he’s going to judge me and leave me if I ever tell him how I got it. Idk how to explain it more to him.