He broke my heart for some random girl! where fo i go from here?

Please help me. He said I was everything to him and that he would never hurt me.. we dated for 3 years about 2 years ago.. and had just recently hooked up again. I'm 22 he's 24 and everything was going great I thought. Then some girl came up and asked for his number they exchanged and when him and I left I asked if he got her number.. he constantly lied to me.. and I believed him. Because I thought he actually cared about me. Then last Friday July 1 him and I were supposed to go to a concert together.. but instead he said he wanted to stay home so I said fine and I went with family. The next day I'm around him the girl and my cousins... and everyone around us knew but me.that he had taken her on a date friday night. My heart is broken.. and now I don't know what to do... he says he wanted me to commit and I wouldn't so I guess he moved on to the next best thing. We've known each other for 8 years.. I don't know.where to go.from here.. I.was supposed to be his everything. Please help me with advice or some quotes to help me through this! I really appreciate it! Sincerely, Erica:)