Marriage and Polygamy After Death

I have heard this verse used to support polygamy, but it actually destroys the idea. According to the law the brother would marry his deceased brother's wife SO THAT HIS FAMILY LINE MIGHT CONTINUE. That is the reason given here.

The same day Sadducees came to him, who say that there is no resurrection, and they asked him a question, saying, "Teacher, Moses said, 'If a man dies having no children, his brother must marry the widow and raise up offspring for his brother.' Now there were seven brothers among us. The first married and died, and having no offspring left his wife to his brother. So too the second and third, down to the seventh."
Matthew 22:23-26 ESV

The first main point here is that the brother was DECEASED. The covenant is ended at death.

For a married woman is bound by law to her husband while he lives, but if her husband dies she is released from the law of marriage.
Romans 7:2 ESV

Any marriage between a married man or woman is adultery, period. Furthermore, any attempt to say that these things are void because of eternal marriage is plainly made erroneous by Jesus. The validation of the Sadducees' question was well founded if there were to be in marriage or family in Heaven. If the woman was married(sealed), to multiple men, whose wife would she be?

But Jesus answered them, "You are wrong, because you know neither the Scriptures nor the power of God. For in the resurrection they neither marry nor are given in marriage, but are like angels in heaven."
Matthew 22:29-30 ESV

Jesus not only plainly tells them there is NO MARRIAGE in Heaven, but He tells them that they obviously don't understand the Scriptures or the power of God. No marriage in the afterlife, yet alone no polygamy.