My Vagina Smells Like Farts. It's Starting To Make My

My vagina smells like farts. It's starting to make my underwear and pants smell. It's to the point that if I scratch between my thighs my hand smells like this foul odor. I have sex on a weekly basis with the same partner for the past year and a half. We do not use condoms but I am on birth control. I use nexplanon. No matter how much or often I was the smell won't go away.