I have been tested positive for chlamydia.

I had a test before my partner and i went away together. And we were obviously together 24/7 on this trip. 

I tested negative.

I then just aftet our trip did another series of tests due to other issues (not genital). And tested positive. I am so confussed. How does this happen. When it was literally impossible for either of us to of been with someone else.. i have been tested multiple times through out our 3 year relationship. And ALWAYS came back negative for everything.

I know it is dormant. But could it of i guess "shown itself" or been "triggered"  in either of us

I am so confused!!! 

I dnt believe it was misdiagnosed as i get checked regularly n usually twice to make sure. Amd its always come back negative. Please help me make sense of this. Because i really dont want to "accuse" my partner of cheating on me..