How do I break up with him?

I'm breaking up with my boyfriend of four months. He is selfish and has made me feel like a bad person. Although he was my best friend and made me really happy at times. He hurt me multiple times as well. And I don't see that ending anytime soon. So I am ending it. I just don't know how. If I should wait until Monday and break up at school. Or if I should text him and see if he is willing to come to my house and talk.