When People Lead Me on for Nothing

This guys at my new school is super cute and is really sweet. He does small favors for me and always chats with me every chance he gets. I started liking him and decided to go after him—after all, he flirts with me every day and on Facebook he just went from being in a relationship to single. Once I got his number and we started texting, he told me he has a girlfriend. Why did you lead me on, then?