I believe that this organism can be transmitted via other routes as well. Clinic equipment is not always sterile!! And unclean clinics aren't all shut down either. Not long ago male gynaes wouldn't even wash their hands after and before "assisting" women in childbirth. Vaginal exams during labor are for example, the main cause for infection.
I have friends who have been monogamous for 20 years, and they got Chlamydia. Their doctor explained to them that dairy is often contaminated with this bug, as cows can harbour it, and pasteurization doesn't always get rid of it...Milk can also harbour other bacteria and viruses.
Just a thought, before you all dump your partners for a disease that is easily treatable, too!