I can sympathize with your problem. I've been struggling with recurring BV for 2 years so I know without a doubt when the symptoms are indicative of a BV infection. I went to a GP and explained the symptoms and she ran the tests and told me everything looked fine. I knew she was wrong so I went to another different GP who ran all the tests and told me I did in fact have BV. I was so mad! In the future, if you know the symptoms you are having are BV and the doctor tells you you're fine, have them run another test. We women know our bodies better than anyone else and we have an intuition about things. If they run the test again and still no positive BV, go to another doctor. It's highly possible that the original doctor doesn't know what to look for BV under the microscope.
The fact that the doctor misdiagnosed you doesn't surprise me when I hear that he/she told you BV is an STD. It is NOT an STD. You can treat your partner but studies have shown that treating the partner is ineffective. BV is caused my fluctuations in your vaginal pH that allow for the "bad" bacteria to flourish while the good bacteria diminish since they can't survive such a hostile environment. So many things can change your pH and often times it's due to hormonal changes before, during and after menstruation. It can even happen during ovulation. My advice to you is to find another doctor.....your health (physical and emotional) is too valuable to put in the hands of a quack.