I am really selfish. I let my best friend in the world suffer for years.
Why did you let her suffer without help?
I liked her, but I wanted her to suffer and not be with anyone else.
It is wrong to cause your friends to suffer for any reason, and very selfish of you.  Your friend has a right to form her own relationships, and you should support and care for her.
Fuck you..
This sounds like a pretty toxic relationship. Are the two of you still friends? If so, it seems like you need to offer an apology for your behavior.