I've never been raped but I am into kinky stuff. I am a member of a BDSM forum and they are pretty helpful answering my questions.

It sounds like you have fantasies of being subdued and punished, and perhaps that relates to your feelings about your rape, only now it gives you a sense of arousal, which is completely normal. I've heard that rape can alter your sexuality quite a bit, and even arousal to rape situations after being raped sounds completely normal.

There's no harm to fantasies--it's not real, and you can enjoy them without being harmed.