Me and my boyfriend went to get tested the same time and now our results are back and his came back as positive (meaning he has an STI) and mine came back as negative... right now I'm so freakin confused, did he cheat on me with someone? I've asked him about it and obviously he's saying he hasn't cheated blah blah blah, I just find it quite impossible how we've been together for 9 months obviously having unprotected sex (I'm on birth control) and he's the one that's managed to catch an STI (chlamydia) out of  nowhere?!??! so confused and upset on what to think :( opinions?