Greetings.
Although BV is not considered a sexually transmitted disease, sexual activity has been linked to development of this infection. It is more of the overgrowth of the bacteria in vagina. Please read the causes of the BV in this resource;
http://www.mayoclinic.com/health/vaginitis/DS00255/DSECTION=causes
There are no over the counter medicines for the treatment, I am afraid.
Please feel free for your follow up questions.
Dr. Arun
Doctor
MBBS, MS. Deal with women related all surgical problems including genito-urinary and breast surgery.