Recurring bv

If your partner keeps giving you bv, are they cheating? I trust my partner and ik he's not, i would still get bv when we were both unemployed and we would spend every day together. We are employed now, I don't use soap down there. Also, in my past relationship i did not get any bv or yeast infections or fishy smell and he was cheating on me with multiple women so it confuses me when i hear people say that recurring bv means cheating. I hear that he needs to get treated as well, he needs to take metronidazole also?