"emotions always get into the mix when you are that intimate with another ..."

No, they don't, though of course they do sometimes for one or other party, and that's usually the place such agreements go wrong. It really does depend on the people involved on whether or not it works for both of them. Take the above 'excerpt' from our Nath there. Based on the poisonous way he talks of his ex "sex-slut" in that tale, he sounds like he got emotionally involved to me and was demanding much more from her than just 'friendship and some sex'. He got emotionally burned and blamed her for shutting him out when he failed to play by the rules.