Forgiveness is a process...
...not an event. Forgiveness is a gift you give yourself. It is the freedom to allow yourself not to be bound by circumstances of the past; not allowing the past to affect your current condition.
By forgiving someone, you aren’t saying that what they did was right in any way. What you are doing is allowing yourself to move forward from the situation, acknowledging what happened has past.
Anger, resentment and holding a grudge against someone for a past event does not effect the other person in any way, it only effects you.