Does he like me? What should I do now?

I'm new at his school. At first he was talking to me rudely. Two months ago at our school's show he was looking at me all the time. Then he was really nice and sweet. One week before I learned that he has an affair with a girl. I was jealous and I started ignoring him and talking to him impolitely. So he was treating me like this too. Now they told me that he broke up with her. My best friend gave me the number of his cellphone. I don't know what to do now. I really like him...