Polyamory is the action of dating more than one partner at one time. Until recently, it was generally Taboo for the mainstream media. . It seems to now be quite popular due to the idea of sex being even more important than ever before, being the "more sex the better, always". Polyamory supporters don't always support Polygamous marriage, though. Most who practice this have the consent of all their women to have sex and date romantically with other women as well, male polyamory seems to be the most common, though female polyamory is on the rise also, both lesbian and female with several men, as it is now more accepted. Some men even have sex with multiple women at once.
Arguments against it
More men still think that one partner at a time is better. Having romantic relationships with multiple people at once is also frowned upon by many because many find it greedy and overbearing, as taking in too much is often met with dangerous consequences. In addition, many of these People are likely not to use Condoms, so the increase in STD's isn't pretty. So it seems to be a rule of decency for many to have one partner at a time. And of coarse, most relationships are deemed to be important and having feelings for more than one makes all seem less important, and most only want one at a time.
Arguments that it is OK
Well it may or may not be consensual, some partners may prefer Monogamy while their significant other insists on dating many others. If they are not telling the main partner that they are dating others that is called cheating, and that is not Liberal at all. Many say that polyamory that is consensual and not cheating is OK as it is only their business and others are not to judge. Another argument is that if you love somebody, you should always go for it, but obviously be careful. Another argument is that a one can truly love more than one at the same time.
Polyamory in Rap culture
Polyamory seems to be promoted in rap Music, and has largely been since the 90's. Songs that feature polyamory were even more common starting around 2012. An example of a recent song about polyamory is Same D*** time" by Future.