Hi missy 1981, I must concur with most of the answers you have receieved. First of all you believe that by sending a letter somehow that will make the abuser empathise with what he did to you, well it might make you feel better but he wont give a damn. Offenders like this are abusers because it is all about their own sexual gratification and no thoughts or feelings of the abused, because if he had he would not of done it in the first place.
I suspect that you could do with councelling to help you deal with your thoughts and emotions and I beleive that there are self help groups out there who can help you to deal with the psychological trauma you have suffered. If you were to contact your local police and speak to their family protection unit, they could guide you to where to seek support with some local organisations. You could even write to the department to receive this information.
In life people suffer from a variety of different experiences, good, bad and indifferent. You have experience of being abused which is horrible, but life goes on. Dont 'beat yourself up', about whats happened to you, you need to deal with it, close the door, and move on.