Mark 12:25 (New International Version, ©2011)
25 When the dead rise, they will neither marry nor be given in marriage; they will be like the angels in heaven.
http://www.equippingchristians.com/Does-Scripture-Support-Eternal-Marriage.php
You know that. . . and I know that. . . but according to mormon doctrine - the 'living' prophet pronouced a different 'revelation' and because they have a burning in their bosom testifying that the prophet is true the new 'revelation' is the correct one.