I tested positive for trichomoniasis, my partner went to get tested his results negative is this possible---and i have been faithful?

Yes: He still probably has them hiding in his prostate. This is the usual situation and he needs to be treated -- in fact, there's not really any reason to look for them, just treat him.

Yes: You could have a false positive. Or it may just not have been transmitted to him. It can be silent in 70% of people, so you may have had it before meeting him.