Does she have a valid reason for wanting you to cut off contact with your friend? If she just wants to be in control you should probably get out of the relationship. If your friend is a jerk maybe you should listen to your GF.
I wouldn't. That's terrible. You shouldn't let him or her terrorize everyone else while they just let you be. It's unfair.
Tell her that using you is wrong and unfair, and you really had real feelings for her all along.
Don't be unfair to the one you have now. Give it time and see if its not just a phase.
Making it unfair to the slaves
a good friend who can sometimes be mean and unfair, but other times nice and will cooperate
Well that's really up to him. You mustn't pressure him though as that would be very unfair on his girlfriend. Just keep in mind her feelings before you act.
Explain to your nana that you really like hanging out with your friend and that you love your nan but you wont stop hanging out with the friend because that would be unfair to the friend if she hasnt done anything wrong.
You should tell her that you think she is being unfair and state your reasons. If you think that she isn't listening and her argument is not justified then you should find some new friends.
You shouldn't do that. It is unfair to that person because you are essentially lying to them. You wouldn't be happy with them either; pretending that you enjoy their kiss or pretending to like holding their hand. You would really hurt this person's feelings by doing this to them.
No cause it's you
I suggest that you discuss this with her parents. Find out how they feel. Don't forget, for them, their daughter comes first.
Depends on the man. Some do, some don't, it is unwise, unfair and impossible to generalise.