Forgive is to accept the other person with his integrity and all his wholeness. To be compassionate and try to understand where he or she comes from, even if it hurts.
Make a work on yourself, why does it hurt, is it reflecting your own behavior, you wish not to have. Is the person, who is creating your harm, the mirror of your behavior. Stay in calmness and integrity to feel what you feel.
If that is the case forgive yourself and be more attentive to your actions. Embrace the other and forgive him, so you can forgive yourself.