There's a universal illness of being controlled by the ego, which is ran by the past. This common phenomenon creates two separate people - the one being ran by the ego (an insane person controlled by the past), and the real person inside. If we can see our true selves, separate of this ego-driven mad person, then we can forgive ourselves and see past the same insanity in others.
Knowing that everyone suffers from this condition, makes it possible to understand that most people don't have a choice in how they act. They are usually always controlled by their past. To harbor resentment towards someone for what they did, including yourself, is futile. Accept it, forgive and make an effort at becoming more enlightened.
There's a meditation I've been practicing to help me with releasing the past and bringing myself more into the present - I thought I'd share... :)
~A Meditation for Releasing The Past~
Close your eyes, take several deep breaths and begin to relax your body and mind.
After a few minutes, begin to imagine past events coming together in a cloud above your head.
Let that cloud that you see just accumulate around your head.
Let it build up. Things from your past that have bothered you, take form there.
In your mind's eye, reach up with your hands and start to form this cloud into a single ball in your hands.
Push all of it together in front of you.
Now look at this mass and see it in your hands. Watch it dissolve into nothing, before your very eyes.
Watch it fall from your hands like glitter, just floating away beautifully.
That's all. It's gone. Release it from your mind completely.
Now just concentrate on the light and energy inside of you. Imagine peace flowing through you.
Sit for several minutes without thought. Just feel. And breath. Be in this moment, completely free of anything past or anything future.
After several minutes, return your mind to your physical body and eventually back to your breath. Sit for a few minutes in a meditative state.