The hardest thing I've ever done.

[BrokenInside]

As for staying friends, if you know you can control your emotions, good for you. I know I can't be friends with her when I am still attracted to her and she is with OM.
Anger and resentment builds up inside you and you are no even aware of it. That is not good for anyone. So no, I won't pretend that I want to be friends because deep inside I know I don't want to.