Am I wrong in wanting my friend to stop being friends with another person?
Why do you want them to stop being friends?
Because she knows I just hate the other person
You shouldn't try to manage who your friend can be friends with. You should just let her live her life.
I want her to experience the same pain and suffering that I am! she needs to know!
I get that you want your friend all to yourself, but that's not very realistic. Instead of wanting this other person to suffer maybe you could try getting to know them. Wouldn't it be nice to have an extra friend in your life?