My god, I feel so fucking sorry for you dude. (thread starter that is)

I would take these people's advice and slip it to her. It sounds harsh, but it's totally necessary. This sounds like some truly dumb, irresponsible ho you are messing with and she is fucking your life up forever, as well as hers.
Don't feel bad, slip it in some nice cocoa or something and smile sweetly as you hand it to her. Once your sure it's all good, dump like you've never dumped before (the girl that is).

Hope it all works out for you man, i'd hate for this to happen to me. Good luck!