How do you help your ex-girlfriend through the agony of your breakup?

It depends on the reason for the break up. If it was because you were courting another person then you have injured her ego. She needs to realize that she is better off knowing now that you aren't living up to your end of the relationship. Healthy relationships are built on trust and if you have deceived her in anyway the trust factor has diminished. This should be a lessoon to both you and her. I hope I have helped you both. Really the best thing for you to do is make it clear that it is over. This may not help her with the agony now, but it will make it so the agony is not prolonged. Don't talk to her too often (maybe once a week). If there was stuff you helped her out with when you were dating that wasn't romantic, still help her out for a while till she gets her stuff together. If you had friends in common, they may be avoiding her because they "don't want to choose between you." Make it clear to these friends that you want them to stay friends with her, and that you won't be mad or jealous (even if you will, a little bit...)