You are correct; there is nothing in Matthew about eternal marriage. In fact, there is nothing in the entire Bible about it! The verse that LDS people primarily use to support their view of eternal marriage and families is Matthew 16:19, in which Jesus says, “And I will give unto thee the keys of the kingdom of heaven: and whatsoever thou shalt bind on earth shall be bound in heaven: and whatsoever thou shalt loose on earth shall be loosed in heaven.”

Mormons teach that the “keys” given to Peter were the keys of the priesthood, which could bind (seal) a couple together through all eternity, among other things. However, with even a cursory reading, one can see the context has nothing to do with marriage or the priesthood. This whole passage refers to the witness of the Holy Spirit that Jesus is the Christ, the keys of authority given to the apostles for the governing of the church, and the administration (or proclamation) of the gospel. For an in-depth explanation of binding and loosing, as would have been understood by the Jewish people of that day, go to Matthew Henry’s commentary at http://blueletterbible.org/Comm/mhc/Mat/Mat016.html

LDS also use Matthew 18:18, which refers to binding and loosing. In this verse Jesus is talking about church discipline; what to do if a brother sins against you. The judgments pronounced by church leaders against the unrepentant sinner will be carried out in heaven (in other words, ratified from God’s throne), while the judgments shall be loosed (not be binding upon) a repentant offender.

Matthew 19:4-6 is another favorite proof-text Mormons use;

And he answered and said unto them, Have ye not read, that he which made [them] at the beginning made them male and female, And said, For this cause shall a man leave father and mother, and shall cleave to his wife: and they twain shall be one flesh? Wherefore they are no more twain, but one flesh. What therefore God hath joined together, let not man put asunder.

Examine the context. Preceding these verses is verse 3, “The Pharisees also came unto him, tempting him, and saying unto him, Is it lawful for a man to put away his wife for every cause?” This sets up the dialogue that follows. Then, in the verses following, 7-9, Jesus tells the Pharisees that Moses allowed divorce because of the hardness of their hearts and that the only grounds for men to divorce their wives is in the case of adultery. He then says, “Whosoever shall put away his wife, except [it be] for fornication, and shall marry another, committeth adultery: and whoso marrieth her which is put away doth commit adultery.”

What comes next is very interesting. Look at the disciples’ reaction in verse 10; “If the case of the man be so with [his] wife, it is not good to marry.” Here is Jesus’ amazing response, amazing because of its conflict with Mormon doctrine;

But he said unto them, All [men] cannot receive this saying, save [they] to whom it is given. For there are some eunuchs, which were so born from [their] mother's womb: and there are some eunuchs, which were made eunuchs of men: and there be eunuchs, which have made themselves eunuchs for the kingdom of heaven's sake. He that is able to receive [it], let him receive [it].

In other words, marriage is not for everyone! Some purposely stay single for the sake of the gospel, so they can fully focus their energies on God and not be distracted by domestic issues. Paul addresses this same thing in his letter to the Corinthians. 1 Cor 7:32-33,

But I would have you without carefulness. He that is unmarried careth for the things that belong to the Lord, how he may please the Lord: But he that is married careth for the things that are of the world, how he may please [his] wife.

If marriage was supposed to be eternal, these would have been good places for Jesus and Paul to say so. Mormons also point to Matthew 22:30, “For in the resurrection they neither marry, nor are given in marriage, but are as the angels of God in heaven.” They use this verse to show that marriage has to be sealed here on earth by the priesthood or else people will have to be single through eternity because after the resurrection it is too late.

In reality, angels don’t marry because angels and humans are two different species. Angels do not procreate. In fact, there is no indication in the Bible that angels are anything else but male. God created the angels as mature beings; they did not start out as babies. God created two humans---Adam and Eve—and they began to procreate by design. This is why marriage was instituted; 1) to put boundaries on sexual relationships, and 2) to model the relationship between Christ and His bride (the church).

"The foundational doctrines of the Mormon Church are not found in the Bible; they come from extra-biblical revelations given to Joseph Smith and subsequent men whom Mormons regard as prophets. Consequently, the doctrinal restoration through the Prophet Joseph Smith involves the revelation of new books of scripture, which Latter-day Saints view as authoritative. Indeed, the Prophet added more to the canon of scripture than any other known individual in history. The Book of Mormon, which he translated, is a sacred record similar to the Bible. But its teachings on Christ and the plan of redemption are unsurpassed. The Doctrine and Covenants contains more than one hundred divine communications from God to the Prophet Joseph Smith. The Pearl of Great Price, a collection of doctrinal revelations reserved to come forth in our day, reveals things not found elsewhere in scripture." (I Have a Question,” Ensign, 1995, 62-63)

By the LDS Church’s own admission, Smith added more things to scripture than any other man. Every major cult and false religion has addtional so-called sacred writings which they claim are equal or superior to the Bible. They contain heresies and doctrines that go against what God has already revealed. Everything necessary for salvation and life has been provided through Jesus Christ. The whole of the gospel is in the Bible.

It is understandable to feel sorrow over no marriage in heaven. We can have confidence that God will not take away from our emotional attachments; instead, He will enhance them. The love we feel for one another here will be increased there, but will not need to be expressed sexually. Marriage was not intended to be forever because our emotional and spiritual fulfillment will come from God. It will be more satisfying than anything we can ever imagine. We will be with our loved ones who have been redeemed and we will love them more than we do now. The problem now is that we want to feel special---or to feel like we have the exclusive love and devotion of another person. That is an earthly desire that we will not have in heaven. Our love will be powerful and all-encompassing and inclusive of everyone. Will we have special feelings for those who were our earthly companions? The Bible indicates we will.