Monogamy also has a storied history of abuse. Up until the 1970's it was perfectly legal for a man to rape his wife. This does not make it fundamentally impossible for healthy and consensual monogamous relationships to exist, and neither does the supposed behavior of 19th century Mormons make it impossible for healthy and consensual polygamous relationships to exist.
What behavior of 19th century Mormons are you referring to? The majority of polygamous relationships were about taking responsibility for widows and their families. Mormons were violently persecuted and polygamy was a support mechanism.
Yeah, I edited it to "supposed behavior" because I don't really have a good basis of knowledge about 19th century Mormons. It's just that, fairly or unfairly, they're usually the ones held up as an example of how polygamy is supposedly abusive and sexist.
