I want him to be mine only mine!!!?

Okay so i was dating a guy for 5 months then another girl surfaced out of no where that he had apparently been dating for 2 months. He wants to keep me as a friend now and she is basically forcing him into a relationship.he tells me he cares about me as a friend not a girlfriend.the other girl is 18 im 19. she is not attractive and doesnt seem very smart.she just spoils the hell out of him. I know me and him have a better connection. It almost makes me luagh to see him with her. Im so crushed overthis. Why is he being so stupid? We still talk everyday and he complains to me about her and tells me sometimes he doesnt know why he talks to her. I know why! She drives him around everywhere and buys him stuff. Me and him actually think on a adult level and have a better connection.feel me? I met her. She is such a sucker. He says he doesnt love her. And still wants to talk to me everyday. They are having alot of and it makes me sick. How do i get him to get rid of her and grow up already? He knows i know why hes doing it. Becuase shes like his own personal slave basically.Im so fed up. Why is he being so stupid? How can i make him mine only mine.he knows im better then her. Im thinking theyll break up soon anyways but if not wat do i do? This guy means alot to me and i know im better for him then her.