Diagnosed with an STI...

So I was diagnosed with chlamydia and I told my partner about it and he also got tested... he didn’t get diagnosed with chlamydia but instead he got diagnosed with Oral and Genital herpes. I’m curious how I got chlamydia and tempted to get retested... I’m just in shock right now.

EDIT: I suppose I should mention that he is 1 of 2 people I’ve ever slept with. The first person I had sex with we were both virgins.