I think the the rules on marriage kicked in with Adam and Eve... so to some degree there have always been boundaries.

I'm sure you could find a wealth of material on sexual attitudes throughout histroy.

Two things I know of personally... though not in great detail... is that modern western ideas are soursed largely in what is called "Victorian Ideals". The Victorians had a very sanatised view of what was sexually acceptable.

the Second thing is Jean-Jacques Rousseau. Who apparently propogated the idea that every male was fundamentally heterosexual and any variation to this came about by corrupting influences during his development... he taught that if a boy could be kept pure (ie: away from corrupting influences ... including masturbation)... he'd be a perfect heterosexual lover for his wife... something like that anyway. Apparently he's been hugely influential on modern Western ideas.

Even the Old Testament laws of Moses' day are flitered through Victorian and Rousseaunian filters by moderns I'd suggest.

I also know something about asthetics... and gnostics... who kinda had the idea back in greekish times that the body was evil and purity and enlightenment (to throw the buddhist idea into this mix) was to be achieved through self-denial of boddily pleasure. But this is an idea foreign to the Scripture.

Well that's all I got.

Blessings
Cat.