BACTERIAL VAGINOSIS, BV????

So I've been dating this guy for a few months now. In the beginning everything was good and I really liked him. After a while I noticed that he didn't really want to have sex. And when we did he would act as though he had no energy. Later down the road I noticed a weird fishy smell in his room after spending the whole weekend apart. I started getting really itchy down there and went to the doctor. Come to find out I have BV. He says he isn't cheating and that I could've gotten BV from anything. Should I believe him??? I really don't trust him at all? Can't you get BV from another woman?