You know, we have to say that there is polygamy in heaven, because Abraham, Isaac and Jacob, the revered ancient prophets, dwell with God, and their wives are theirs eternally. So at least someone in heaven has an eternal, plural marriage. However, the Lord upholds our free agency in all cases, both on earth and in heaven. The first wife must approve. We will have preferences in the eternities as we do on earth.

Something else to consider — In the scriptures, it says, “Therefore, I would that ye should be steadfast and immovable, always abounding in good works, that Christ, the Lord God Omnipotent, may seal you his, that you may be brought to heaven, that ye may have everlasting salvation and eternal life, through the wisdom, and power, and justice, and mercy of him who created all things, in heaven and in earth, who is God above all” (Mosiah 5:15).

When we are sealed in the temple, we are also sealed into God’s eternal family, on condition of our continued worthiness. This is another blessing of eternal marriage many people don’t consider.

All the best to you and your friend.