Every experience has it's own story. I can understand why some people are unable to forgive and why others feel it's necessary even when everyone around them believes them to be a fool.
I experienced some abuse from my baby's father. After a long break/temporary restraining order (with him having some time to think and sort himself out) I have forgiven him. If I hadn't; not only would he have to live with the resentment, but my daughter would have to live with me resenting her father and I would've had to live with resentment in my heart...never good for a peaceful life!
(wikipedia: If you hate your enemies, you will contract such a vicious habit of mind...)
She now sees her father sometimes and I truly believe that he would never do anything to her; but I do keep my eyes very wide open. I never had problems with him while he was sober and he stays sober while she's in his care (we don't allow sleepovers) because he knows how important it is to do so.
I think that forgiveness is important; if not for the abuser---the victim certainly deserves a clear mind. My advice, is to never forget so as never to make yourself vulnerable enough to be put through it again.
However, Forgiving, forgetting and going back to normal is likely to welcome more abuse. If in a relationship, the victim needs to get out of it asap. The abuser needs to know that the victim is not afraid to leave. However, some people can change. The ones who are willing to admit they were wrong and take themselves straight to anger management/AA meetings/rehab/counselling---those that are willing to do whatever it takes to prevent it from happening again after the first time have hope. But the ones who turn it all around are rare noone should live in fear. The victim also needs to find a way to increase their confidence through counselling/therapy/self defence classes...again; whatever it takes...and not to go through it alone!!!