Forgiveness has always been a tough subject for people. It's easier for most to hold onto the pain that someone has caused, so as to remind them not to let their guard down again. As a result, this thought is subtly imprinted onto the subconscious, which in turn results in more of the same experience. You are literally telling the Universe that you are craving more of the pain, and so it's job is to give you more of what you desire.
The key to understand here, is that forgiveness is actually quite unnecessary. We make a drama out of it, but in reality there is no need for the fiasco, if we simply understand that not everyone understands who they are. They are simply operating from their own preprogrammed subconscious, which often times, is full of garbage. If they knew any better, they would treat you better. It is because they don't realize the light within themselves, that they can hurt others. When a person knows that they are the same as their fellow man, they will not find the need to compete, manipulate, deceive or betray another. They will understand that our bonds with each other must come from love, and therefore it would be impossible to hurt another. So forgiveness is not necessary. Acceptance is. Once you accept people for who they are, you won't find the need to get angry with them, or even feel hurt by their wrongful actions. Instead you will know, that if they knew better, they'd do better!