Check out the leading picture. It says it all.
Polyamory is for women to sleep around within “marriage.”
Polyamorous relationship touted in JAX FL: (“fallen pregnant” rolling eyes)
https://www.dailymail.co.uk/femail/article-7759411/Polyamorous-woman-20-fallen-pregnant-one-FOUR-partners-went-away-together.html
With predictable consequences:
https://thepostmillennial.com/polyamorous-man-featured-by-progressive-media
https://www.jacksonville.com/news/20200325/jacksonville-man-jailed-in-abuse-of-5-week-old-baby
Polyandry is ahistorical and not supported by human biology. It is usually only attempted in these times as a stunt based on some feminist political ideal. In practice, the strongest man will eventually drive the others away.
Polygyny, on the other hand, is essentially the default state of pre-civilized humanity. High status men invariably have relationships with multiple women, even if law denies "wives" two through infinity the official status that concubines had in earlier times. Women have proven throughout history they prefer to have 10% of a high-status man than 100% of a low or even middle-status man. Women who sleep around within marriages today are expressing buyer's remorse and seeking out that high-status man they didn't get the first time. Law cannot change this behavior.
Our civilization recognizes only monogamous marriage in an attempt to minimize the social disruptions caused by rampant polygyny. Those disruptions, however, are likely to be less troublesome in these times - when other entertainment options such as pornography and video games have already greatly minimized the desire among low status men to spend time and effort raising their status just to compete for female attention. We are already seeing the return of an ancient system - a small percentage of men doing most of the procreating.