Throughout history, men have argued that it is in their biological nature to desire multiple partners. Over time, we have evolved towards taking a partner in order to help raise our children and enforce a set of moral codes that contradict our stronger physical needs.
I've only seen it argued by a very few dissipates and scientists, the latter wishing they were the former.

As far as "our stronger physical needs" are concerned, there isn't a shred of scientific evidence for the greater "sexual need" of men, anymore than there was the medieval conclusion that women had a greater need. IMHO, and for what little that's worth, it's just more "the two genders are two species" propaganda.
[ 03-04-2002: Message edited by: fable ]