@Goretantath
That's some wierd assumption. Actually you can use other mammals as reference and primates especially. Most animals are driven by hormones in their sexual relations and they are not conscious about it. Our ancestors started to form groups (see the chimps) probably as soon as they came down from the treetops. Though their preferences in partners were animalistic (means that females fall for the strongest males and males fall for the beautiful i.e. healthiest females), didn't mean that sexual relations in primal communities were mostly chaotic and unsocial. But I won't deny that rape occured from time to time.