Mixed Feelings

I am in love with a boy. My friend likes him. They used to be together, but she dumped him and went for one of his friends. I was there for him during this time. Then she got sick of his friend and wanted him back. Me and him were getting closer but now she's back and he wants her again. Why is he so dim? He keeps calling me "quiet." I don't know what to do. I don't know if I can stay with them both if they get together. It hurts.