I guess part of it, I refuse to be the sexual property of another, so it would be pretty messed up for me to demand it the other way.
I see things the same way.
However, most of the women I had deals with don't care a bit about being free (as in "not sexual property"). They just care about getting the exclusive rights, and are ready to give up their sexual freedom for it - at least in the relationship negotiation phase. There might be truth in the evolutionary explications for this kind of behavior.