[george wythe]

Even polygamous marriages are about the sexual union of man and woman.

Do you happen to know what happened to Brigham Young's marriages according to Mormon theology after he died?

Is Brigham Young still in a polygamist marriage to his 56 wives, or is he united to only one of them in the Mormon afterlife?

[Angelus Errare]

Not sure about the Mormon afterlife being a Catholic myself, but my understanding is that mainstream LDS church believes that polygamy is not inherently sinful but rather that they should obey the laws of the land on this particular issue.

[webstersII]

"Is Brigham Young still in a polygamist marriage to his 56 wives, or is he united to only one of them in the Mormon
afterlife?"

Yes.

And not only that, there are many (dozens, perhaps? no one knows for sure) other women since his death who have married him in absentia, expecting to be united with him in the afterlife.