i didnt even realize they were dating. its surprising how open Glen was about it in an interview he and Marketa had when they were promoting Once. He said, "The idea of kissing and hanging out is just really pleasant," to which Marketa burst out laughing. He also said "There's always been an attraction, of course, and I think were just giving it a shot."
http://youtube.com/watch?v=7fWCTOR5xtk