Granted the Mormon doctrine of sealings (eternal marriages), it is not surprising that they would depict Christ in such an arrangement.
On October 6, 1854, Latter Day Saint "Apostle" Orson Hyde stated:
"We say it was Jesus Christ who was married [at Cana], to be brought into the relation whereby he could see his seed, before he was crucified" (Journal of Discourses 2:82).
On March 18, 1855 "Apostle" Hyde said:
"I discover that some of the Eastern papers represent me as a great blasphemer, because I said, in my lecture on Marriage, at our last Conference, that Jesus Christ was married at Cana of Galilee, that Mary, Martha, and others were his wives, and that he begat children" (Journal of Discourses 2:210).
Mormon Apostle Orson Pratt agreed with his contemporary when he wrote, "Now it would be natural for a husband in the resurrection to appear first to his own dear wives, and afterwards show himself to his other friends. If all the acts of Jesus were written, we no doubt should learn that these beloved women were His wives" (The Seer, p.159).
On page 172 of the same book, Pratt wrote, "We have now clearly shown that God, the Father had a plurality of wives, one or more being in eternity, by whom He begat our spirits as well as the spirit of Jesus His First Born... We have also proved most clearly that the Son followed the example of his Father, and became the great Bridegroom to whom kings' daughters and many honorable Wives to be married."
In a letter dated in 1963, the man who would become the tenth LDS President [highest LDS officer], Joseph Fielding Smith, answered the question "Was Christ married?" with the words:
"Yes! But do not preach it! The Lord advised us not to cast pearls before swine!"
Full article from Mormon Research Ministry.