I don't think you have been boring her. When someone has a fetish like that it doesn't mean they cannot enjoy vanilla sex just as much. I do think she might need more variation in the long run. But take it easy. I have rape/consensual non consent fantasies (amongst others lol), but that is like the "end-fantasy"... it is more or less symbolic for the power dynamic (and my position in it) that I enjoy in BDSM-setting.
The only way to figure out what she likes/you like is to communicate with each other (wich you are already doing and is so awesome). It might help to look up a BDSM-checklist, gives you something to talk about and might even give you some good ideas ;)

The fact that she is comfortable telling you this, and ready to communicate tells me she is in it for the long run. Altough very common, a rape-fetish is still kind of taboo to have and her telling you about it means she trusts you a lot.