That's the funny thing I'm learning, it's almost IMPOSSIBLE to just be "friends" with a woman, especially if you guys are having sex consistently. And Don't let the sex be some crazy out of this world shit with puddles of cum everywhere. All of the stuff you are describing above is damn near impossible with a woman when the element of consistent sex is there. They're going to want more and whatever "deep friend" or whatever you thought you had goes out the window. Ultimately, she will find some dude who is willing to be with her on more "official" terms and you will be an after-thought. I mean sure she may pick up your calls from time to time or you may fuck every blue moon, but priority still goes to the new dude in her life. Isn't that how it really goes?
I'm also learning that sometimes IT DOESN'T matter if you tell the girl you don't want a relationship, just wanna fuck, blah blah blah. That's the least you can do if you don't wanna go there but even that isn't enough. IF the person is feeling you, they will hold on with some un-rationalized belief system that maybe one day you will magically be hers. I think Kai was right above where a women can save herself a lot of time by sensing this and being strong but that is far from the case with like 99.8% of women. Hell, I'm sure she was even once that woman so she learned from that experience...