A lot of people ask me why do I have to forgive? They did such an horrible thing to me!
You don't have to forgive them for them, you need to forgive them for yourself. You need to peace of mind right? By forgiving them you will get the peace of mind. I'm not saying go back and start talking to them. Forgive them and move on. If we keep a grudge, we won't be able to move forward, our energies will be stuck. To release those energies we need forgive and learn the lesson they taught us, so the pattern doesn't repeat in our life. And even if it does, the next time we know how to behave and conduct ourself.
A small prayer that always works for me when someone has hurt me or I know I have hurt someone. I just close my eyes and imagine the person in front of me and I say
"Atma Nameste,
We are all children of God, We are all evolving, We all make mistakes, You are forgiven, Gods blessing be with me and you."
This prayer is by Master Choa Kok Sui - my spiritual guru!
Hope this helps you!
Sending you lots of love and light! :)