Simple q ... just need ur opinion please please ..something about me and my boyfriend ?!?

okay so i have a boyfriend ! he has his best sister ... and she is treating him wierdly !! i dont know .. ever since ... she is like always callin him "my (his name)" !! and she is always with him !! he spends more time with her than me and come back and say that he loves me more and adores me and so ! she is always like beeing tooooo sweet with him and always alover him !! i got realllly jelouse cause she was like doing it on perpuse! cause everytime she sees me she goes to him and say "my (his name)" !! and when i tell him he doesnt see it that way ! soo i told him not to talk to her again !! he took it so hard cause she is his best sister !! and he doesnt wanna stop talking to her ! he just says i will talk alil !! and with everytime he goes to her .. she must do something that makes me jelouse !! and even when he told her that he cant talk to her much bec i get jelouse ! she still talks to him !! an information for you --> he is always tellin me not to talk to guys and i do what he says .... so do you think i should tell him that i wont do wht he says unless he do what i say ?? or tell him its okay and leave them that way ?? or just get upset till he stops talkin to her .. or you have another opinion ?? ...