How to explain to my Bf I have bacterial vaginosis without him thinking I could have an STI

I (26f) have been faithful to my boyfriend since day 1 of knowing each other (31) and been in a relationship together for a year now. However I have been experiencing discharge and pelvic pain. I visited my doctors office and was diagnosed with BV. I was given antibiotics for it but it keeps coming back. However I know it comes back bc I wear tight undergarment (fajas) and I workout often and don’t always shower right away. My hygiene is really good but because of the tight clothing and sweat it has caused BV. I know he is a curious person and will search it up and the first thing that comes up on the internet is “sexual activity: having new or multiple sex partners” I know once he searches he is going to question me. However the reason why I have BV is so dumb.