Should I stay in my friendship with someone I've known for 14 years?

Okay I soooo know how this feels like. My advice is to tell her a piece of your mind and don't leave a single thing out. It will hurt especially if your really close, but in the end its worth it. Unless she seriously changes though I wouldn't keep being friends. It's not worth it. And when its all over with you will probably be able to move on and be kind of liberated. Hanging out with other people to get your mind off it will help afterwards too.