Since you had negative tests before, you can be pretty certain your infection was acquired since your previous negative tests. Also, although can be carried by
womenWomen's way for up to 4 years, it is rare; about 90% of cases clear up on their own within a year or so. So I doubt you have been carrying chlamydia for 4 years. It is possible but very unlikely.
And chlamydia is only acquired sexually. So if you have it and you had sex with nobody else, you had to get it from your current partner.
There is only one other possibility, and that is that your positive test was a false positive. That depends a lot on the type of test done. If your provider did one of the older tests, such as a "non amplified probe test" (i.e., the Gen Probe company's Pace II test), it might have been in error. For that reason, most labs don't do that test any more. More likely you had a nucleic acid amplification test, such as Aptima (also produced by GenProbe), Amplicor (Roche), or Probe-Tec (Beckton-Dickinson). If so, a false positive result is very unlikely.
I hope this helps. Good luck-- HHH, MD
HHH, MD