He gave me WHAT!!?

Hello, I am posting this anonymously because I don’t know what kind of reaction this will get but here it goes.....

I have been with my man for 2 years now. We have a wonderful relationship. I love him and we want to marry in the next few years..... we do share each other with women from time to time, that is something we agree upon and it has been great! Now I get tested every year. I tested just before my relationship and was clean, he has told me he never has had one (lucky) but he does still get tested. I have also been testing every year since being together. April 2019 was the last time I was tested and I was good. My boyfriend went to the doctor like the second week of January and his results were also negative. Now just a week ago I went in for my yearly PAP and my OB asked if I wanted to be tested. I thought I’m here why not, I should be clean but why not check anyways? That was a Friday and then Monday I received a call saying I had Chlamydia! Now I’m not a doctor but I’m pretty sure the only way to contract this is through sexual interactions. Now to MY knowledge we have not slept with anyone since the last time I was tested. We live together and spend an average of 98% of our time together. And again, just in January he was tested and it was negative. Now get this, just 4 days before this we got into a huge fight and he said he needed space and left, he said he went to his grandmas house which I know is true, I just don’t know what else he did..... I’m just very confused. I don’t know how to process this.... he hasn’t been upset or angry at me which also makes me fee like he is guilty of cheating.... idk maybe someone reading this would have more answers for me..

Thanks for reading, sorry it’s long.