You need to back off, period. His gf always comes before you and rightly so. If his gf made a post about " bf has a female best friend who wants to always spend time with my bf" , guess what people would say about you?? 


If you were truly his friend you should respect his choice and leave him alone. Stop meddling with his relationship.

Are you sure you aren't in love with your " best friend " cuz otherwise I don't understand why you get so upset about not hanging out with him every day