Do Christians believe that God has a wife?

Answer 1

Most members of the Church of Jesus Christ of Latter-day Saints (the 'Mormon' church) believe that God has a wife. (although the general consensus is that He has only one). This doctrine has never outright defined by the Church, but it is implied by the Mormon belief that no man can enter heaven without a wife, and that we as the offspring of God could not be created without the union of a man and a woman. This is an idea that is rarely brought up within Mormonism, as the role is considered to be extremely sacred and not something to be treated lightly.

Here are some quotes from official Church leaders and Church resources that mention "Heavenly Mother":

"When we sing that doctrinal hymn and anthem of affection, "O My Father," we get a sense of the ultimate in maternal modesty, of the restrained, queenly elegance of our Heavenly Mother, and knowing how profoundly our mortal mothers have shaped us here, do we suppose her influence on us as individuals to be less if we live so as to return there?"

-President Spencer W. Kimball, April 1978 General Conference

"We forget that we have a Heavenly Father and a Heavenly Mother who are even more concerned, probably, than our earthly father and mother, and that influences from beyond are constantly working to try to help us when we do all we can."

-President Harold B. Lee

"Building upon the foundation laid by Joseph Smith, subsequent prophets taught that God was not single, but married; that there is a Heavenly Father and a Heavenly Mother; and that we were made in their image: male and female children."

-Sister Ida Smith, August 1980 Ensign

Additionally, the Church-publishd "Proclamation on the Family", issued in 1995, states that we are spirit children of "heavenly parents".

If you are interested in reading more, the Wikipedia article found at the "Related Links" below is very well researched and informative.

Answer 2

No, marriage is only a relationship made for humans.