Cheater or loyal??

So I've been with my boyfriend for 2 years and we've both been head over heels in love. Everybody always says they wish their bf would look at them like mine looks at me. I just tested positive for chlymidia however and I have been tested for that a year ago by my obgyn and it was negative. I haven't been with anybody but him since our relationship began and I thought the same about him.. But now I'm obviously not so sure. I know it's an std but it can also be spread through blood on blood constant and he's a wrestler so that could be one possible way he got it.. He has also been blackout drunk 3 times at different parties so that could also be a possible (but heartbreakingly terrible) way he got it. I need some opinions because I reallyyyy do not want to break up and he doesn't either but I don't think I can stay with somebody who cheats