Bv over and over again

I keep getting bv back to back to back and can't figure out the reason my bf and i stopped having sex and I just still seem to get bv. I've started taking prebiotic eatinf healthier and still nothing has changed. Each time I go to the doctor she gives me metronidazole which ends up giving me a yeast infection so she either gives me the cream or pill for that then bam 2 weeks later I have bv. Has anyone had this issue before if so what helped you clear it up im so over this and don't even know what to do.