HI!
Normally there are a lot of lactobacilli or "good" bacteria present in the vagina, and these bacteria keep other bacteria and yeast from causing symptoms of infection. It is important to keep the "good" bacteria healthy so that they can fight the "bad" ones like the ones that cause BV (gardnarella, etc). You can do this by taking probiotics and also live culture yogurt.
BV is not really a sexually transmitted disease, and won't harm a developing baby. There is some evidence that links BV to preterm birth however, so it is good to clear it up if at all possible. Antibiotics kill the "good" and also the "bad" bacteria, so that can be a reason that some people keep getting BV-yeast-BV over an over again.
If you can, use Metrogel or Cleocin ovules for the BV and take diflucan for yeast.
For symptoms of itching and burning, you can use vegetable shortening topically.
It is cheap, no prescription needed, and works pretty well without causing any additional inflammation. One other thing to try is a strong anti-inflammatory cream such as clobetasole--your MD will have to prescribe this one.
I hope this helps!
Dr B