Off Smell

I have been noticing for weeks now that my discharge has an off deep nasty odor to it. I can't describe it well, but I was tested for STDs and it all came back negative and they said I didn't have a UTI. No matter how much I shower or anything if I scrape out the discharge it still smells. I dont discharge in my panties and smell it , its only if i pull it out. My boyfriend smells it during sex and hates it. I've noticed over the weeks its not as strong but i dont know what it is.

Any ideas?

Std and uti have been zeroxed.