Telling partner about STI

Hi, I'm very concerned about telling one of my partners about the fact that I potentially have Chlamydia. He's aware of the fact that I have multiple partners as I am polyamorous. We have only had vaginal intercourse twice (using condoms) but frequently engage in oral sex. In the past month I have one partner who I've engaged in unprotected sex with and one I've had protected sex with in addition to this partner.

The reason for my major concern is my partner's high anxiety with sex and STIs in general. I have herpes, which he's aware of and that is part of the reason he has anxiety about having sex with me. But aside from my issues he's had a long history of anxiety and depression surrounding sexuality and some other sexual dysfunction.

He is a very good friend and I don't want to lose him. I know that he will freak out when I tell him and I am worried this will set us backs lot in regards to our relationship progression. I can't take ownership of his freak out but I am so worried he's going to have a low opinion of me and distance himself because of this.

Do you have any advice for how to handle this situation?

Hello, I would try to help you.
I don't know you, so I don't know if my advices will be helpful but I will try.
I suggest you to speak about this problem with a friend of you that knows you well and may support you.
Maybe is not a great advice but this way you can get the support you need.
Another advice is to have protected sex and to make a medical exam to see if you have Chlamidya.
Sorry for my bad english.
Good luck.