Daniel answered...

When married by earthly power and the authority of man, our vows are "Until death do you part."

We believe that families can be together forever as part of our Heavenly Father's Great Plan of Happiness. His Work and His Glory is to bring to pass the exaltation and eternal life of man. He wants us to be even as He is and to return home to live with Him again.

Through the ordinances of his Holy Temples, God's son's and daughter's are able to make covenants. Through the power of His Holy Priesthood, be sealed together for all of time and eternity as Husband and Wife, parents and children.

Families were designed and instituted by God with the intent that they be forever. The love we feel in this life does not need to be cut off when we die. Those who have already died are not lost us forever. God has mercifully made a way by which all who would accept these saving ordinances can do so, living or dead.

We perform these ordinances for those who have in the past died so that they may have the opportunity of accepting them on the other side if they so choose to do so.