Looking for a best friend

Don't know how I manage to make best friends throw me away. Its happened twice. We get close, they tell me I'm an important friend and I can take it to the bank so to say. Then things happen and they decided we aren't friend any more. After not having friends for so many many years I left them get close. Now it makes me afraid to let someone become a "best friend" I don't want to get hurt any more. I guess I better not let anyone get close again. Better keep my guard up.