I don't think that you should be feeling guilty. You state that you felt like a rapist, but I don't think you have any reason to. While you liken your experience with your wife to a rape, in an actual rape there is one key component that is missing that was not with your wife: consent. I know that emotionally the experience was very traumatic for you but I just wanted to point out that logically you have reason to feel guilty. I hope this is some help.