One of the values of having a metaphysical stance which includes the possibility of It Just Is as an acceptable terminus to the demand for causal explanation - is that it ends the infinite regress, and the problems which that brings with it.
The Mormon belief is that we are in some literal sense the children of God. then there is the fact that on earth children are produced by two parents. Further, the Mormon doctrine is that all Men are either male or female from before mortal life - and the complete unity of Man is therefore the dyad - a couple sealed in eternal marriage.
Considered together, all these tend to imply that God the Father must also have a 'consort' specifically a Wife, and also a Father and Mother in infinite regress.
God's wife is termed Mother in Heaven.
I would classify the belief in a Mother in Heaven as (on the whole) mostly a 'folk' belief among Mormons because it is not required of Mormons, and there is virtually nothing on the topic (explicitly) in Mormon scriptures, and the belief in a Mother in Heaven has from not-much to zero impact on the major aspects of Mormon life and discourse.
On the other hand, belief in a Mother in Heaven is not ruled-out by LDS authorities (as the linked entry in the Encyclopedia of Mormonism makes clear) - and the reality of a Mother in Heaven has apparently been a belief held by Presidents and other General Authorities (including, probably, Joseph Smith - if the King Follett discourse is regarded as definitive rather than speculative thinking-aloud).
The Mormon belief in a Mother in Heaven is therefore not so much a matter of revelation or teaching, as a matter of the logical extrapolation of implicit doctrine.
If the principle of parenthood is taken to be universal, then every person must have two parents - including God the Father - ergo God must have a Wife , and must have been the Son of another God.
But the principle of parenthood need not apply to God the Father.
If God the Father Just Is - eternally; then he may also be:
1. The unique instance of a parentless personage; and also
2. The unique example of a being neither male nor female, but one who alone is able to procreate spiritual children.
Indeed, if these two things are accepted as part of primary reality (they Just Are); then this disposes of almost all the most significant arguments that Mormons are not-Christian.
Because such a God is the One God - past, present and future; He is primary, unique, eternal, unbegotten, Father of all - and so on.
In sum, God the Father is not just the one God of this universe, but the one God of all reality - and He is unique in his Nature.
To assume that God the Father Just Is also disposes of any necessity for positing a Mother in Heaven.
My impression is that the Mother in Heaven is a long way from being central to Mormon doctrine - since it is possible to go for months, or even years, of reading books, articles, theology and journalism about Mormonism and not to come across any reference to Mother in Heaven: indeed, to forget about the idea altogether...
My interpretation is that some Mormons have been led, by their metaphysical assumptions concerning the universality of sex and parenthood, to generate theological modifications including infinite-regress of parents (and universes) and a Wife for God the Father - but these additions have made very little (if any) difference to the actual 'popular' daily beliefs and practices of most devout Mormons.
In this respect, it seems that the Mormon Mother in Heaven has developed in a manner opposite to the Roman Catholic conception of the Blessed Virgin Mary - Mother of God.
In the Catholic tradition, the veneration of Mary was first established in the popular everyday practice of liturgy, prayer, iconography, art and devotional life generally - and only later, sometimes many centuries later - were theological modifications (e.g. the Assumption, the Immaculate Conception) introduced to justify and explain these practices.
So the Catholic Mother of God was venerated in practice primarily and long before theory; while the Mormon Mother in Heaven seems to be mostly (for most people) a projection of theological theory; and not much (or at all) venerated in practice.