Here is a summary of what Mormons believe concerning marriage and what the LDS marriage ceremonies are like. This information includes quotes from the Encyclopedia of Mormonism. This is a work published under the supervision of the Quorum of the Twelve Apostles of the LDS church and produced in 1992 under the direction of an editorial board comprised primarily of BYU faculty and staff.  Elders Neal A. Maxwell and Dallin H. Oaks of the Quorum of the Twelve Apostles "worked closely with" the committee that prepared it, according to an article in the LDS Church's Ensign magazine, March 1992, p. 79. The article heralded the Encyclopedia of Mormonism as a "landmark reference work.")

Mormons are taught that marriage in the temple is essential to eternal life in the highest level of the Celestial Kingdom (their highest level of heaven).  Marriage—Mormon marriage in a Mormon temple—is a pre-requisite for one day progressing to be a god like God the Father is now a God. This is held out as the ultimate goal for all Latter-day Saints.

It must be understood, however, that to be married in an LDS temple one must have an LDS temple recommend.  To get a temple recommend one must successfully undergo a recommend interview in which one meets with one’s bishop and another LDS Church leader (member of the stake presidency). In this interview one is asked, among other things if they: are a full tithe payer (10%), have abstained from coffee, tea, tobacco and alcohol, are morally pure, and totally support and respect Mormon Church leaders. If found worthy, members are given a temple recommend card which is valid for one year. At the end of a year it must be renewed by undergoing another interview.  According to a recent PEW survey on Mormons in America, about 65% of US Mormons say they hold a current temple recommend.

Here are some quotes from the article "Marriage" in the Encyclopedia of Mormonism, vol. 2, pp. 855-857. Words in all UPPERCASE indicate additional encyclopedia articles.

"Marriage is more than a matter of social convention or individual need fulfillment in Latter-day Saint society and lifestyle; it is central to the exaltation of the individual person.... Thus, Latter-day Saints consider it of utmost importance, (1) To marry the right person, in the right place, by the right authority; and (2) To keep the covenant made in connection with this holy and perfect order of matrimony" (Mormon Doctrine, 2^nd ed., p. 118).

"Central to LDS theology is the belief that men and women existed as spirit offspring of heavenly parents in a PREMORTAL LIFE. Latter-day Saints view life on earth as a time to prepare to meet God and strive toward becoming like him. Becoming like God is dependent to a large extent on entering into 'celestial marriage' for 'time and all eternity,' for eventually all exalted beings shall have entered into this highest PATRIARCHAL ORDER OF THE PRIESTHOOD. Latter-day Saints believe that the marital and family bond can continue in the post-earth life, and indeed is necessary for ETERNAL LIFE, or life in the CELESTIAL KINGDOM with GOD THE FATHER; MOTHER IN HEAVEN; JESUS CHRIST, and other glorified beings. Given these doctrines, LDS marriages are distinct and different in several aspects from marriages in other denominations, and marriages of faithful Latter-day Saints differ from those of less observant Church members." (Encyclopedia of Mormonism, pp. 855-56).

ETERNAL MARRIAGE (p. 857)

"The principle of eternal marriage and the ordinances implementing it constitute a very distinctive and valuable part of the Church. It involves a ceremony performed in a holy TEMPLE by an officiator endowed with the PRIESTHOOD AUTHORITY to invoke covenants intended to be efficacious for TIME AND ETERNITY. This is a sacred and simple ceremony to unite husband and wife in the bonds of everlasting love and in the hopes of eternity" (pp. 857-58).

"...The sacred ceremony of temple marriage is conducted in reverence and simplicity, and the occasion is a beautiful and joyous one for Latter-day Saints. The bride and groom meet with family and friends in a designated sealing room of the temple. The officiator typically greets the couple with a few words of welcome, counsel and fatherly commendations.... The couple is invited to come forward and kneel facing each other across an altar in the middle of the room.... The sealer pronounces the simple words of the ceremony, which promise, on condition of obedience, lasting bonds with the potential for eternal joy between these two sealed for eternity.... At the conclusion of the ceremony, the couple kiss over the altar and may then arise and leave the altar to exchange rings" (pp. 857-58).

[Note: The only family and friends allowed are Mormon (LDS) ones who are considered worthy to have a temple recommend. If you are a non-Mormon or an unworthy Mormon you are not allowed inside an LDS temple and cannot attend the wedding ceremony even if you are an immediate family member of the bride or groom.]

This marriage ceremony is also performed for dead relatives who never went through it themselves, in the hopes that the deceased people will accept the Mormon gospel in the afterlife and then have a chance to become gods themselves. Living Mormons stand in as proxy representatives and go through the ceremony for those who are dead.