Growing apart from your friends...?

Has anybody ever had a friendship that they outgrew but the other person didn't? How did you handle it as in were you subtle or downright blunt about it? I have a friend who I don't want in my life anymore. She is fairly insecure and basically instead of opening up to me she just acts in denial of her problems and subtly takes them out on me. I have tried talking to her but she just won't talk about anything and its so unfair then that she just treats me in a certain way to make herself feel better. More the fool me I guess for stickin around. I have various plans to travel and move out and this friend is insistent that we do everything together. I guess I have to bite the bullet, stop being so nice and just do my own thing regardless of whether she gets offended.? What do you think? I just feel so held back.