Not asking if I have a chance with my best friend, how can i explain my friendship to the girl I'm dating?

any girl you date would have to understand that you and your best friend share a very special bond but it's no more then friendship, it will take some time for sure.your friend means so much to you and plays an important role a your life so it's obvious for your girlfriend to feel a little uncomfortable in front of her. just try to make her understand that both the relations r totally different and you also try to understand her cause the way she is acting is natural.you can also ask your friend about how she and her boyfriend handled the situation back then when they started dating.GOOD LUCK