How can I get my best friend's girlfriend to chill?

my bestfriend(a boy) and I are really close we tell each other everything but I don't know what to do about his g/f. she thinks that I am in love with him and that he loves me. we are always cursing about this. what should I do?

wait what your boyfriends girlfrind arent you your boyfriends girlfriend?!?! im confused?!?

First, don't think there's anything wrong with drawing back just a tad with your BFF. Not a forever thing, but you want to be on good terms with this girl and if you guys are young, it can be a hard thing for her to accept. Then, try to make friends with her. When you are around the two of them, make the focus more on her and getting to know her more than you and your BFF making jokes and whatnot. Talk to her more than your BFF and she'll start to develop a bond with you and feel like you're her friend, too.