Why is he a jerk and is it my fault?

He likes you and now he dates a new girl. He thinks he does not need you. Plus he still likes you and he feels hurtful when he sees you. Do not feel anything since you know what you are doing. Just be yourself and see thing above him. Then you will feel better after you analyze him. You always will be his friend why not help him? Do not bring guilt trip to yourself. Time to do well in school that my advice.