Telling someone about an STI

So I just found out today that I have chlamydia and I’m super freaked out because I’ve never had anything before. There are 3 people who could have given it to me, because I was clean before them and I’ve already told one. I’m telling another one anonymously, but I’m really scared about telling this guy who I deeply care about and losing him even though it’s easily treatable. Someone please help by giving me an idea of what to say to him when I call. Thank u so much.