Ok, this might sound weird, but if you made an effort, could you smell any kind of oniony smell? Any discharge? IF so, there might be some kind of infection going on.
If not, either you might not be very hygienic (not that I think that's true but I had to mention it!) or maybe you just ate a lot of onions recently? Seriously, after you eat something strong smelling like onion or garlic, your skin it gonna leak it out a bit. Know what I mean?
Anyway, if that doesn't seem to explain it, I'd see a doc.
Since it happened with both boyfriends, I think it must be something in your diet too. I agree that maybe you should really see a doctor if things like that aren't a constant or substantial substance in your diet.
ok this is gonna sound weird, but any time i have accidentally, say, scratched my armpit for example and then forgotten and put my fingers in my mouth, i taste onions. it doesn't smell like it but it tastes like it. think it might be bacteria from your armpits rather than your breasts. is this possible?
yeah i know, i sound weird now. i don't lick my armpits regularly or anything lol, but it is just something i have noticed by accident!
If you eat a lot of "spicy" foods, or "spiced" foods the smell comes out of your pores, especially after you sweat. Before anyone goes and says onions aren't considered spicy... wrong. They have a very strong taste, especially when eaten raw. Do you eat a lot of onions? That could be the culprit... or do you possibly sweat more than the average person? It could also be that you aren't "fresh" (by fresh I mean recently showered) and you have been sweating throughout the day ... it just takes a little sweat for the bacteria to multiply and cause the smell. Thats pretty much all I have to say... Good Luck!