Why does bacterial vaginosis keep recurring every month after i treat it?

Bacterial vaginosis: The bacteria responsible for this can be difficult to erase, and is easily acquired by sexual activity. What causes a "discharge, odor and other symptoms" is not always a bacterial agent, but can be multiple other organisms, including parasitic ones. Since this seems to be difficult to eradicate, see your gyn provider for an exam, possible wet smear, and treatment.