Odors can be caused by bacteria and other infections. Are you have any other sympoths..Discharge of any kind? I would say to see you GYN so they can do a culture and see if anything grows. Then they will be able to treat you. Best of luck!
It could be Bacterial vaginosis (BV) is the smell there all the time or just when you have sex? because having sex when you have BV can make the odour a lot worse.
Vaginal odors can be cause by bacteria/yeast infection. Do you have discharge? I suggest you see your Gyno. Make sure you get a pap once a year.