You should not feel any shame no matter how much guilt you have from keeping a secret from your most precious loved one.  

As a victim, no one knows what you went through and have felt over the years with relation to your specific crime except for you.  

I understand how she must feel and why you feel guilty.  She’s upset that you weren’t able to open up to her about this and that she probably feels like she could have helped you cope over that period of time as well as she’s probably angry that someone did it to you.

I’ve been trained and done advocacy for victims and will say this to you.  It is your story to tell when you are ready.  It is your choice to choose who you tell it to.  No one else’s.  You are the victim and everyone else needs to remember that.  

If you’re looking for ways to mend your relationship with your wife, I’d suggest either reading material related to advocacy, get involved in a program where she’ll understand the perspective better, or even just try to find some counseling services that deal with this specific scenario maybe even just meet up with a victim advocate in your area so she can see and hear how you’re feeling and understand why you didn’t tell her.