Odor that came out of no where

So about two months ago I started getting this really bad odor that I've never had before and it's noticeably bad during sex. At first I thought it would go away but it didn't so I went to my gyno, she examined and tested for infections and stds everything came back perfect. I've been with my boyfriend for 3 years so it's not different partners, I'm not on bc and nothing's changed in my diet really. I'm hoping someone has experienced this and can help me, I don't know what could be wrong and I really hope I'm not stuck like this.. It's ruining my sex drive and making me so uncomfortable that I want to run to the shower immediately after sex which is really taking a hit to my self esteem. Please help me with any suggestions or ideas.