Sorry, I shouldn't be baiting you..... there are well argued sociological studies that show why this need is always segregated from all others and is defined in moral terms: like so many other social regulations, this has an economic basis too, dating back to the days when patriarchy was first raising its ugly head.
C i don't mind at all i love questions because it sharpens my mind.
as for the answer. It is an appetite just like any other and it is legitimate one too, and i don't consider it immoral either. Its a natural act and nothing wrong with it.
it however leaves one very vulnerable in every aspect so its important to share it with someone who you feel you have a connection with and love...the works. and it all boils down to self preservation and not for anyone else but for yourself