I'm sorry that happened to you. Give yourself time to get over him. Don't do anything hasty in the meantime. Enjoy time with your friends and do things that you want to do. Keep evolving as a person and some day you will want to take a chance again. Not every guy is a creep or liar. You'll find one that deserves your love some day but until then focus on what makes you happy. I'm sorry for your pain. (Oh and the other chick got what she deserves if she knew he was in a committed relationship and still dated him)