Suggest Treatment For Bad Odor In The Vagina

I have a horrible onion smell in my vagina. It all started in my late teens and I ve over and over been told that it is BV and everytime I get prescribed either anti biotics,or oinment gel or cream. NOTHING has worked it has been years that it gets really bad or becomes somewhat tolerable bit it has never really gone away. And now after having my 2nd child it has been at it s absolute worst! I have tried apple cider baths, tea tree oil trements, raw garlic treatments,baking soda baths, no underwear at night, loose clothing etc. And this is all after years of what the doctors have given me not working. I haven t always smelled like this down there and I refuse to believe that this is normal as the docs lik to tell me when they can t come up with a conclusion. Ive been to about 4 different doctors and I can t take this anymore. I m only 23 years old and this is so embarrassing. Please someone help me!