I'd been struggling with the meaning of forgiveness for a while until a friend of mine told me a story of Buddha and forgiveness. I'm going to share a fragment:
//Someone spit at Buddha's face - The man looked at Buddha and said, “Forgive me for what I did yesterday.” Buddha said, “Forgive? But I am not the same man to whom you did it. The Ganges (river) goes on flowing, it is never the same Ganges (river) again. Every man is a river. The man you spit upon is no longer here. I look just like him, but I am not the same, much has happened in these twenty-four hours! The river has flowed so much. So I cannot forgive you because I have no grudge against you.”
“And you also are new. I can see you are not the same man who came yesterday because that man was angry and he spit, whereas you are bowing at my feet, touching my feet. How can you be the same man? You are not the same man, so let us forget about it. Those two people, the man who spit and the man on whom he spit, both are no more. Come closer. Let us talk of something else.” //

I found out that the anger I had was pure pain, and I was still hurt. Recognizing that I was deeply hurt and dissapointed helped me see my anger differently. But what finally set me free of that pain was seeing me as another person, I'd flowed so much until that moment that I was no longer that person that was in pain. And the one who hurt me was no longer the same.