Weird odor after sex and period

[actorgrl04.livejournal.com]

Over the last month or so I've been getting a weird odor coming from my vagina, usually after sex and sometimes after my period. It's kind of a foul fishy smell. I haven't had any weird discharge or discomfort, just a weird smell, which is annoying because I'm the only one who smells it. It goes away after a while, but comes back when I drink coffee.
I'll also add that it do shower pretty well after I have sex to wash down there, and that does help sometimes. I also have only had one partner( my long time boyfriend) and we've been together for over a year.

Any idea what this is and what I can do to keep the smell away?

Thanks!