There is no pit so deep that God's love is not deeper still. - Corrie Ten Boom
Many years ago, when I was first starting to "deal" with my childhood and the long term effects of sexual abuse, I went to talk to a priest about my struggles to forgive my father. He told me about the true story of Corrie Ten Boom. She and her sister had been placed in a concentration camp during WWII for hiding and protecting Jews. Her sister had died in the camp.
For years Corrie Ten Boom traveled the world with a message of hope and God's love and a powerful message of forgiveness. Then one time when she had spoken about forgiveness, she saw a man who had been one of the guards in the concentration camp. She prayed to God that He would forgive the man for her because she did not think she could forgive him. When the guard reached her, he put out his hand. She forced herself to take his hand and felt such warmth and strong love from God, she knew then that God had forgiven him for her.
So the priest told me to ask God to forgive my father for me. And so I did. And tears came to my eyes and I knew that, while I did not feel like I could forgive at that moment, that God did forgive him for me.
Over the years I have forgiven my father many times. It seems like a lifelong process for me. And when I have a hard time forgiving him, I do what Corrie Ten Boom did - I turn it over to the Lord. He is much better at this forgiveness thing than I am.