False Positive Chlamydia Test

Has this ever happened to anyone?? I tested positive for chlamydia at my 1st prenatal appointment. I have been faithful to my husband for 6 years. He tested negative, he retested and was again negative. He also took a blood test and has no antibodies for the virus. I didn't retest because I didn't know a false positive was even possible - I just took the antibiotics and assumed the worst of my husband. I am beyond baffled. How could I test positive, after being with only my husband for the past 6+ years, and he is negative? I just saw on another pregnancy forum that it seems to be common...? It has caused so much strain on my marriage.