25F how do i tell my bf (28M) that i have chl*mydi*?

So my bf and i have been officially together since july, we started talking last april. i didn’t cheat on him let’s clear that up, i love him very much and wouldn’t even consider it. even when we had just started talking, he was the only person i was sleeping with. i must’ve got it from the guy i was seeing before him, but i don’t have any symptoms, and i thought we were only sleeping with each other so i didn’t feel there was a need to get tested. last week i was at the doctors, and they offered to test for stds, and i said sure why not im already here, then the results come back positive for chl*mydi*. i don’t know how to tell him, any advice? what are the chances he stays with me? pls help i want to tell him sooner rather than later.