The Sealing Room

There are several sealing rooms in each temple.
The bride and groom kneel at the altar facing each other.
Their families sit behind them on either side.
Holding hands, the couple make covenants with God and each other to be faithful to each other and to God and to keep His commandments.
Couples sealed in Jesus' name, by Priesthood Authority in the temple are set apart to be sealed by the Holy Spirit of Promise for eternity, not just "til death do they part".
Mirrors are placed on on walls across from each other, so the couple can symbolically see themselves together through eternity.
The Bible precedent for this is found in Matthew 16:19, "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."