A monogamous relationship is what the average person strives for ever since they are a teen. I used to intensely be like this, i thought a good relationship was the ultimate source of fulfillment, not anymore thanks to TRP, but this mindset caused me extreme grief and depression. Striving for a relationship applies to both genders, the guys are usually looking for a gf while the girls are usually relationship-hopping, spending less time being single than with someone. This may be more pronounced in my conservative country but still. The question is:

Why has society been built like this? Is this part of the female imperative or is this simply the model to make men work the most (i.e. eventually getting married and being straddled to bringing bread home, motivated by their wife's pussy)?

If it is part of the female imperative, then how does it benefit women?

Edit: Also how does this apply to societies where harems were/are permitted? The fact that the most powerful men were the ones with the biggest harems makes me wonder if this is what would be most fulfilling for a man in terms of sex and love life.