Tservo, I have a friend who sounds similar to what Brian stated to you. For him there is this voice in the back of his head that says all the talks and meaningful conversations, the going out to movies and/or dinners, the shared interests, and the enjoyment of each other's company may just be a giant con, a cruel trick being played out for some selfish ulterior motive. For him, he has learned the intimancy of mere friendship is no tto be trusted as some can put on a convincing false face.
He feels sexual intimancy can strip these masks off, make someone bear their true self, be true to their nature, if only for a moment. Now sometimes after the sexual intimancy has occured, he has concluded that it has been all just bullshit and sometimes he has thought there just might be something true hear in friendship but it has been only what he has felt in the sexual moments that he has trusted and used to read the relationship.
I would say it was I who asked him had he ever had a friend he hadn't slept with. After thinking about it for some time, he answered, perhaps a lttle surprised at himself, NO(myself included)