Let me assure you that what your father did was a sin, and God detests what he did even more than you do. Abuse within marriage is wrong in God's eyes, because the abuser is breaking the vow he or she took before God to cherish and love their spouse as long as they both shall live.
At the same time, have you ever asked yourself what it is costing you to stay so angry at your father? It doesn't hurt him; from what you say elsewhere in your letter, he has no desire to see you again. But it does hurt you! Study after study has shown that bitterness and anger are like festering sores that eat away at both our minds and our bodies–and our souls. The Bible tells us not to be like those who "are full of bitterness and captive to sin" (Acts 8:23).
Forgiving someone doesn't mean we agree with what they did, or that we pretend it never happened. But it does mean we let go of our anger and bitterness, and we refuse to let them have a hold on us any longer. The Bible says, "Get rid of all bitterness, rage and anger, brawling and slander, along with every form of malice" (Ephesians 4:31).
How is this possible? It is possible only as we turn our lives–including our anger and bitterness–over to God and seek His help to overcome them. It may not be easy, but begin today by opening your heart and life to Christ's transforming power.