Mormon beliefs about heaven differ from orthodox Christianity by having multiple heavens instead of a single heaven. Mormon teachings describe a Celestial Kingdom, a Terrestrial Kingdom, and a Telestial Kingdom. There's nothing like this in traditional Christianity — it's not even comparable to the doctrines of limbo and purgatory in Catholicism.

 

What Are the Mormon Heavens?

According to what the Church of Jesus Christ of Latter-Day Saints teaches Mormon believers, the Celestial Kingdom is the highest heaven.

This is where God lives and, if you are good enough at following all the religious laws laid down by God, you will be able to live in this heaven as well.

The Terrestrial Kingdom is the second heaven — it's not as good as the Celestial Kingdom, but it's still heaven. Here you'll find all the people who faithfully followed the Law of Moses, but didn't live up to the laws which Joseph Smith allegedly translated. They are allowed to go to heaven, but not the best heaven that's reserved for Mormons.

The Telestial Kingdom is the lowest of the three heavens in Mormon teachings and the only people found here are those who have managed to follow "carnal law," but who didn't live up to any of the religious laws considered valid and legitimate in Mormon tradition.

 

Mormon Texts on Mormon Heaven

The Mormon scripture Doctrine and Covenants of the Church of the Latter Day Saints: Carefully Selected from the Revelations of God has this to say on heaven in Mormon teaching:

They who dwell in his presence are the church of the Firstborn; and they see as they are seen, and know as they are known, having received of his fulness and of his grace; And he makes them equal in power, and in might, and in dominion.

And the glory of the celestial is one, even as the glory of the sun is one.

And the glory of the terrestrial is one, even as the glory of the moon is one.

And the glory of the telestial is one, even as the glory of the stars is one; for as one star differs from another star in glory, even so differs one from another in glory in the telestial world... (Doctrine and Covenants 76: 94-98)

 

Mormon Marriage and Mormon Heaven

The marriage vow "until death do us part" doesn't apply to Mormon marriages because, according to Mormon teachings, people who marry on earth will continue to be married when they go to heaven — at least, they will if they are Mormons who get married in a Mormon Temple.

This doesn't apply to everyone else, so non-Mormons who are married on earth apparently won't still be married in heaven. However, it does seem to apply to Mormons who have polygamous marriages. According to Mormon teachings, then, there are women in heaven who are spending all of eternity sharing the same husband with dozens of other women.

They aren't just sitting around, basking in God's glory, either. According to Mormon teachings, married couples (or groups, in the case of polygamous marriages) continue having sex in heaven. Lots and lots of sex, too, because this is how they produce "spirit children" which will be used to populate the planets which they are gods over. This is something all Mormons are supposed to believe, but it's not something you're likely to hear Mormons talk to outsiders about — especially prominent Mormons like Mitt Romney.

 

Christianity, Heaven, and Marriage

This differs from traditional Christianity which doesn't say anything about marital relationships in heaven, though the implication is that marriage no longer exists after physical death. Marriage is something that exists solely for a person's physical life and isn't a relationship which a spirit or soul can enter into.

This is probably because, historically, marriage has been tightly bound with a variety of social goals which only exist in physical life: economic security, familial alliances, procreation, etc. None of this is supposed to exist in heaven according to traditional, orthodox Christianity. In Mormonism, however, sex and procreation do continue to occur in heaven so it only makes sense that marriage would continue to exist.