Is it okay to Vitamin C before symptoms?

My actual question is at the bottom of this post if you'd like to skip past my specific history.

I am 22 and got BV for the first time a few months ago :( I have now gone to the doctor about 5 times... 2 of the times were just pure paranoia of thinking I had it when I didn't.

The only time BV ever comes on for me (or at least I think because this is when the smell happens) is during sex. The first time I got BV it was during sex so strong and gross, then a weird (but not the fishy smell) for a few days, then I had sex again and the really gross miserable smell happened again and I figured out I had BV. I went back to my doctor and she treated it and told me to take pro biotics every few days (now I try to take one every day)

The next time I got it was the 3rd time I had sex with the same guy. I smelled it a couple of minutes into sex and just stopped as fast as I could. The next day when I went to shower/check out the smell it didn't even smell bad, but it hurt really bad. I started treating it the next day because my doctor gave me extra medicine in case it happened again.

I am going to see this same guy in 2 weeks, and while I don't have BV right now because I just treated it I want to be proactive and put vitamin C up there.

My question is: if my current pH balance is normal and I don't have BV is it a bad idea to do the vitamin C treatment? Should I just do the treatment maybe like 2 days before I see him? I am so horrified and embarrassed about this and I don't want it to happen again.