But I wonder if this gray zone is not simply the symptom of massive loneliness.
I often say to friends that I'm surprised how much, when I'm in a relationship, I see all (other) women as men. Even when other women try to engage me into seduction play, it just makes me laugh or mocking them, just like I would with men (providing they know I'm with someone, of course, or else I try to be less rude).
This gray zone seems to me like people are incredibly lonely and craving for sexual activity, and I think we can spot that in our societies way beyond those "sexism at work" problems (the "dating" thing where you meet people you hardly know, "social" activities like facebook, etc).
It could be also a thing for people that are prone to cheat, but I can't think it's a majority of people.