No, simply fucking not, polyamory relationships didn't exist and just existed when someone could have made empires which lasted less than 100 years with these type of relationships (just like females not working thanks to not knowing biological differentiations or forcing them inside because a lack of knowledge around sexual behavior, fear around an illegitimate son which doesn't happen naturally or just a difference on his sexual organ), it wasn't really common, the people who say otherwise are wrong.
I will explain why that's the case in our inner biology.
1. Sexual Organ
Our sexual organ on men and women is oversized, oversized organs normally refer to a social species, so this isn't the end point of the argument, what is the end point of the argument it's how much we can last in sexual intercourse, poly amorous species normally last less than 10 seconds or much less, this is because they need to inseminate as fast as possible to get to their next mate, in comparison, humans normally last 7 minutes until ejaculation in men without any problems, even more if the foreskin is present. Having the pattern of a monogamous species in our sexual act makes our relationships generally monogamous, even more when we have specific pleasure body parts which aid around mantaining semen around on the same area.
2. Social Relationships
Human social relationships normally had gregarian societes which aid eachother and hunt together, in these types of societies you cannot make polyamory because of the simple fact that everyone has the need of protection and function, polyamory on gorillas happens because they live on smaller packs, have more physical strength, don't hunt, aren't carnivores and because they have the need to make new settlements, humans never did any of this, humans in comparison live on bigger packs where a dominant male can be killed rapidly, have less physical strength so we can't defend against an entire group of 25 people, we hunt so our resources are used around killing other animals rather than dismantling other gorillas, we eat meat which makes us more responsive to general fights against other animals and generally we don't escape from the family circle, in this type of society, is better to not use resources to kill everyone else and just lend a mate for each men.
3. Reduced sexual dimorphism
even if we are different, our sexual dimorphism it's really reduced and it's just the separation of different strengths which complement on the same jobs, most polyamorous species in the lower scale are 3x times stronger on all areas in comparison to the females, in the worst cases, species can be 7x or more times stronger than the females, in comparison, humans have a small 2x difference on arm strength and a 70% general women force on all areas. this gets more specific because woman have a lot more resistance and are better on a lot of areas which men don't have, these strengths are just things which separated to aid eachother, being a more useful sexual dimorphism that is separated to help on the same things like hunting (this can be seen on our strength, enough to fight with other men, but not to defend from other animals, polyamorous animals attack each other and are strong enough to defend everything from other animals, humans don't have that), exploration or tasks which require more balance (and this is without any real information around female strengths and training, at most there have been studies around pill use and differences between performance, something which people haven't accounted in most studies around a lot of stuff, this isn't to say that there isn't any difference, but that we don't know everything we should know), obviously there's some specific jobs, but these are so small and just reflect around 1% of them (fighting against other men, which you do once normally (even more when we weren't close to eachother on the first place) and women using their smaller hands to grab small stuff, which again, it's only done once.)
4. Reduced force
Our reduced force is an example of a more monogamous species, being weaker relates to using groups and intelligence instead of a singular force which can defend, this makes humans monogamous as a basis to help close dynamics and survive, thus making monogamy the main aspect of our existance.
5. Increased intelligence
Our increased intelligence makes monogamous relationships more logical, they are more based around intelligent response, they are less violent, more functional, use resources much better, reduce parent seeking thus downtime and in conclusion more children, this relates to the big groups that humans had, this makes monogamy the only reasonable choice.
6. Weaker children
weaker children which need more time to walk means that they aren't useful for 4 years, this makes the tribe have the need to aid the mother so the children don't die, men included, the act of taking care of children in a mutual environment relates to a monogamist setting, this has been proven by a lot of studies which show that men have a similar response of a reduced sex drive after having kids and caring for them in their first 6 months of life, something which polyamorous species don't do.
As you can see we are monogamous, societies where people had isolated experiences, extremely big empires which broke after 200 years and other socialized components aren't a representation of nature.
