Pain is temporary. Quitting lasts forever.
Winners are not afraid of losing. But losers are. Failure is part of the process of success. People who avoid failure also avoid success.
You build on failure. You use it as a stepping stone. Close the door on the past. You don't try to forget the mistakes, but you don't dwell on it. You don't let it have any of your energy, or any of your time, or any of your space.
Every adversity, every failure, every heartache carries with it the seed of an equal or greater benefit.