What do I say to my ex who cheated on me almost the entire relationship…?

and he is still with that girl. He had sex with me monday(presidents day) and told me all of this. told me he still loves me, but he is with her. told me he cheated on me. I tried pushing him out of my life but i cant. and he wants me to wear his necklace everywhere i go..and stupid me fell for him and wore it in EVERY SINGLE one of my senior pictures ): I still love him, after everything he has put me through. Even though he cheated on me..i still love him. My heart wont let him go. What do I say to him…