I need some advice or opinions I guess. This might be a bit gross or TMI so stay with me lol

So a few times (might be 2 or 3) that my boyfriend has finished in me I have had a foul smell down there the following day. It is fishy and just pungent. Now individually neither of us has any thing odor like that. Last night after sex I took a shower and washed meticulously (or so I think) down under to prevent this smell. But I still had it. Idk why this is happening or what to do. I will not that I can remember one time when I accidentally forgot to throw out our room trash and a condom was there for a while, and it had a similar fishy smell. But I assumed it was left for a bit. Idk but it’s driving me nuts, please help!!