Board Thread:Spoilers!/@comment-6175354-20141215234519/@comment-1894786-20150318063849

There is a theory that Regina did in fact lose her virginity to Daniel. And was subsequently pregnant when Daniel died. Cora would've guessed this somehow, and on the night of Daniel's death, forced an abortion potion down Regina's throat, causing her to lose the baby. People theorize this is the true reason Regina hated Snow so much. Because her not keeping the secret killed not only Daniel, but their baby.

But that seems far too dark for Once, and even if it was true, since it's never been brought up, bringing it up now would make it seem... cheap somehow, like they just threw that in there.

But I personally believe she lost her virginity (unwillingly) to Leopold, may have had a few rolls in the hay with Jefferson, definitely had sex with Graham and then Robin.