How do you get back at your ex for cheating on you?

You do what would hurt the person's ego most: You act indifferent toward the breakup as if it would not take much for you to move on and find someone better. NOTHING destroys an ego more than to think your ex didn't want or need you as much as you thought. If you do things like act crazy to hurt them back, it will only AFFIRM to them that they have the ability to affect you so much and you adore them and are hurt immensely and can't recover for a long while. However, to see you go on with your life with a new person taking their place is the ULTIMATE knife in the back to a cheating ex.