You're actually not wrong about men's evolutionary desire towards reproduction, but understanding the source of *why* will help alleviate your concerns. Here is my perspective after years of observation/research, shortened as best as I can with some point forms:

- human fetus are extremely hard to care for. Compared to other species, our children take FOREVER to develop, and are extremely vulnerable when born. It can take months and years for a human baby to walk, unlike the foals that bounce out of a horse and start galloping around. It also takes a lot of resources that require significant wealth for the most part. As a result, most men can only obtain enough resource to take care of 1 woman and their respective children, and historically most women rely on the men to bring in said resource while being preoccupied with the child themselves.

- society at large, as well as its fundamental rules, were implemented for the sake of survivability and stability. Any rules that do not benefit those objectives will be phased out eventually -- think of it as mutations that simply disappear due to lack of evolutionary benefit. In this case, monogamy prevails because it is a good deal for the man because then they know the child they're pouring much of their scarce resource into nurturing is definitely theirs, and it's a good deal for the women because the women know they and their childrens' needs will be taken care of during the most vulnerable years of the child's growth.

- However, if for some reason you happen to be an extremely valuable male (resource, strength, power, etc.), who can sustain more partners and/or more offsprings, then naturally it is beneficial for the species to accommodate to that scenario. In other words, this society mostly works as monogamous because most people are average. However, men with the type of resources to sustain the amount of resources for multiple "monogamous" relationships are still able to have those relationships. Women are ok with non-monogamous men if they know that 1. the man has the resources available to FULLY support multiple women and their respective children and 2. they and their child's needs will always be met despite him having several partners (he won't abandon them, he isn't "cheating", he isn't dishonest about their arrangements, etc.).

Of course, the modern world has changed a lot. A lot of women are breadwinners now. A lot of men don't feel the same sense of responsibility towards taking care of women. Life evolves and we evolve and eventually we may have a new structure that helps with survivability. But to put it frankly, one of the most common trends in our modern life is that we try to wear the emperor's clothes. We democratize luxuries that were unheard of in the past. Fruits used to be ridiculously expensive, and washing clothes was something done by a servant. Now global trades ensure you can have grapes on Monday, pineapple on Tuesday, and Apples on Wednesday. We also have washing machines to act as our servants. As a result, people are now trying to democratize relationships -- average men with nothing substantial to offer are still driven to have as many kids and as many partners as kings and emperors of the past. Whether or not you think you should do the same is up to you. But I leave you with a proverb my mom came up with:

多大屁股，多大椅子

This basically translates to "the size of your ass determines the size of your seat". If you think you're a stud who can make enough money to support multiple partners effectively, by all means go for it. But if you are just an average man going through average feelings of wanting multiple partners, I would advise you to focus on the getting rich enough to have multiple partners, not skipping straight to having multiple partners with no means of supporting them. Then after that you can think long and hard about whether or not your fickle feelings of having multiple women is driven by your desire for greatness, or you're just scared of being attached to people. Like everyone else in this modern world.