I understand completely the need to have new and exciting sexual experiences. But, there are so many other things that the two of you could do to...spice things up that don't make one or the other of you uncomfortable.
One thing that my fiance and I have started doing recently is writing erotic stories for or about one another, or simply about fantasies... it's difficult sometimes to put wants or needs into words when speaking. I find writing to be very helpful and it can ignite all sorts of new and fun ideas.
Risky sex can be exhilarating, but you can create that same feeling by introducing new things into your sex life, even if it's something as simple as a blindfold or a little extra time taken to do not so typical warm ups during foreplay, If she isn't comfortable with the idea of public sex now then it won't be fun for her so why push,you know?