Bad smell during sex?

So a lot of times during sex there will be a horrible smell like the room is filled with fish I’m not sure why this is. I clean myself properly and shower and my boyfriend says he showers before he sees me and none of us smell before we have sex when we go down on each other or do foreplay there is no weird fish smell/taste so I’m not sure why there is one during intercourse. We are not sure which one of us the smell is coming from but it makes me feel embarrassed and worried to have sex. Anyone have any idea what could be happening?