You're only looking at it from one point of view, the view that confirms your personal beliefs. You're not looking at anything else.
The most populated countries in the world, India and China, don't have divorce rates that we have in the west. India is the biggest democracy in the world.
What you say about peer pressure may be partly true, but these societies also take marriage very seriously. You don't enter into marriage quickly and the whole family is usually involved. It could just as easily be said that our divorce rate in the west is high because people get married for flimsy reasons, like Vegas weddings, or for health insurance (in the U.S.). Or people prioritize love as a marriage ideal when that is a very recent phenomenon.
Actually, the archeological evidence, mostly from burial sites, shows a lot of couples buried together, often ornately. There is more evidence of pre-historical human marriage than not. We also know this is true from indigenous oral histories that have been passed down through spoken word and not committed to writing.
Humans have never been pack animals. Our species has had organized tribes from as far back as the archeological evidence allows us to look. Comparing us to other hominids is pointless. Our nearest relatives, the chimpanzees, have sexual patterns that humans don't share.
Pre-historical marriage was likely the norm because infant and mother mortality were much higher. If men wanted to see their progeny survive they had to be able to directly care for them. And women were not going to mate under unstable circumstances because pregnancy could cost them their lives. Tribal societies were structured around this basic fact, which led to elaborate rituals around marriage, and even women becoming property (something I don't agree with) because paternal protectionism became so paramount. The division of labour was also centered around this. Women were domestic because the female side of reproduction was costly. So the men had to go out and do all the hunting. That was the reality of the world until industrialization. People didn't live as long, women died more often in childbirth, and children died more often from diseases we now take for granted. In wars, the men also died en mass. The family unit was much more prioritized and was tied to the community of other family units. It still is today, despite the propaganda. Pre-industrialization, unless whoring was your profession, then you would not do well in society if you behaved that way. Sluts (male and female) are universally distrusted for that reason. They lead to reproductive instability and disintegration of the family.
I think you should stop projecting your laissez-faire views on history and pick up a history book. The main reason that modern people can have loose morals is because of the invention of birth control in the 20th century, modern luxuries that reduce community dependence, and our food system. If modern society collapsed tomorrow we would go right back to a traditional, agrarian lifestyle because it would be the only way to ensure survival. Basic biology doesn't care about contemporary opinions. Those opinions can only flourish because of modern decadence.
If you want to be a whore, go be a whore. It honestly doesn't matter to me. But I won't abide shallow arguments about history and "human nature" like comparing us to felines, who, by the way, are many shades different than primates; and, among primates, humans are very unique.
haha.