A WOMAN used post-it notes to expose her cheating boyfriend while documenting their nine-week vacation in Europe. The anonymous girlfriend posted her videos on TikTok under the username @iknow_girl and went viral with her story. She began uploading the videos detailing her story on July 31, as she set about exposing her then-boyfriend to social media. But she did so in a rather unique way. In every video she'd hold up a post-it note in front of her posing boyfriend in the background, detailing their romance. She signed everyone with the hashtag "I know", to confirm that she knew of...