Chlamydia Bathhouse Japan

i recently treated for chlamydia which i contracted from my Japanese boyfriend. I have been with him for over 3 years and he is the only one i have been sexual with, and the same for me so he says. The situation is he lives in a dorm in Japan for his work and says his doctor said it was possible for him to have contracted the std from the public bath tub in his dorm. He is adamant that he has never cheated and that this is the only possible answer. I couldn't find any reliable sources that this is actually possible. Only a few travel websites and one med one that says its technically possible because chlamydia is a bacteria but its a less than 5% chance. I just would like to know if this is ACTUALLY possible or if he is trying to save his *** and the relationship. i dont wanna lose him if its possible true but i also don't want to stay in an unfaithful relationship.
Any help would be greatly appreciated.
Thank you.

[JessyJames2010]

So you know pretty much, chlamydia is an STD, --you have to have sex to get it.   I read many situations like yours on the threads and the doctors (dr.hook/dr.hhh) have said that, "virtually all chlamydia cases have been aquired through sex period."  People have asked if you can get them through towels, or swimming pools, or toilets, or brazilian wax procedures, and they've never seen a case.  

You want to know if getting chlamydia is ACTUALLY possible from a public bath tub.
The only way I can see this happening is if the person before him ejaculated all over the tub, that would require alot of ejaculate (maybe an orgy of people) and the tub was full or vaginal/penile secretions, and then this person (who provided the ejaculate) would have to be infected, and then your boyfriend would have to purposely want to get infected by rubbing his penis especially the penis tip all over the ejaculates on the tub.   This is even known to be a low risk activity for chlamydia and gonorrhea.   Sorry if this sounds  a little silly, but that's the only non-sexual way I cant think of; and even that there has to be some sexual activity.