Can you be friends with your ex?

Allie

2 1/2 Years later and he doesn’t want to be in a relationship. I’m 19 and he’s 21. He believes that I’m still inexperienced and that he’s holding me back from growing. We’ve had our fair share incidents that led to our break up but this man is my whole world, best friend, Supporter, you name it. He still wants to be close friends but I know if he so much as flirts with a girl I’m going to LOSE IT. What should I do?