Forgiveness is not about keeping score, it's about losing count!
Many times in my life when I've been let down by someone else, or have been treated unfairly, my first instinct has been to lash out; to make them feel bad for hurting me. But, forgiveness is necessary for healing.
Unforgiveness builds up resentment, anger and you then dwell on how much someone hurt you. It's a huge barrier in finding healing and peace.
We can't do this on our own. We can do nothing without God's grace, let alone forgive someone.
Let God in the midst of the turmoil; trust that He is reliable and that in this trust, we can find peace and healing, and eventually the ability to forgive.
Luke 23:34 - "And Jesus said, "Father, forgive them, for they know not what they do." And they cast lots to divide His garments."