You forgot one prominent category my friend. There are many girls out there who are very open about sex, and many couples enjoy watching porn together.
In fact, my avatar acquired a copy of "Lover's guide to better sex video series - 10 secrets to great sex", and I believe that secret 7 was all about this topic. Basically, it was said that watching adult movies as a couple was beneficial to the relationships. Not only because they get to learn and try new things, but because it greatly intensifies the act! So next time you go to the video store, don't forget to get a couple of videos!