Marriage is for This Life
Luke 20:33-34 "Therefore in the resurrection whose wife of them is she? for seven had her to wife. And Jesus answering said unto them, The children of this world marry, and are given in marriage:"
It is very doubtful that the situation that the Sadducees were relating ever took place. It is more probable that they were stating a hypothetical case to complicate the understanding of the resurrection and thereby discredit it.
If you accept their basic supposition (marriage continues in heaven), then their reasoning was correct. It would not be possible to administer marriage in heaven with multiple mates as their story described. Their reasoning wasn't flawed, but rather the "facts" that their reasoning was based on were not scriptural.
The scriptures speak of two becoming "one flesh" in marriage, and angels are not flesh. Paul said, "Flesh and blood cannot inherit the kingdom of God" (1 Corinthians 15:50). Therefore, marriage is an earthly institution limited to flesh and blood mortals and will not exist in heaven. Marriage, as is death, is temporary for mortals while they are on earth. This is why a person whose mate has died, is free to remarry. Marriage pertains only to this life.
That is not to say that a couple who have loved each other deeply here on earth will love each other less in heaven. God forbid. They will love each other infinitely more, but it will be God's "agape" love (not romantic love) and it will not be limited to just one person. We can be sure that heaven will surpass any expectations that we may have so that no one will be disappointed.
Today, many people use logical reasoning to try to discredit God's Word. But Jesus said, "They err because they do not know the scriptures." Therefore, their arguments have no merit; only reasoning based on scripture has any merit.