I am someone who firmly believes that you can't really genuinely fall for someone or love them until you really know them, and you can't really know someone until you spend time with them and in person. And not just a couple dates, it takes time to get to know someone. Someone who falls fast for me or falls in love just from a few emails, chats, etc, that is a red flag for me because they don't really know me. They are falling in love with some image they have of me, and not the real me, since they don't really know me.
It sounds like this person you were dating, genghisfaw, is really immature and you dodged a bullet. Good luck on your dating adventures!