And how far back does the historic data you have go?
You wont like where that goes.
Early in the evolution of early modern humans, there was a significant ecological catastrophe that nearly destroyed the human race. We know this from the extreme reduction in genetic diversity in later fossil specimens, which reached very close to the limit of what is possible for a species to endure before it cannot recover, due to genetic bottlenecking.
This meant that mate selection was seriously pressured, and that intra-familial mating practices were the only game in town. (eg, incest. This has been determined using genetic testing of ancient remains) When taken with that angle, generalized human behavior under mate scarcity pressure results in lots of unsavory behaviors, even in modern humans (which we can use to help better understand the group behaviors of such societies). In populations where there is no strong established governmental force to enforce a restriction against ... certain practices... those practices will proliferate. See Africa, posted prior.
The horniness is not going to diminish, even when there are no mature women around-- basically. This leads to unpleasant realities as likely consequences.
It took many thousands of years for the human race to return to a large enough population for such reproductive pressures to diminish to levels sufficient to even ALLOW the invention of agriculture that Reelya mentions.
This reality alone substantiates my statement.