This is a question people have been struggling with, and efforts to clearly define marriage have been elusive. Is it for the happiness of adults? Is it a sexual relationship? Is it for formalizing committed relationships between people who love each other? Why can it only be between a man and a woman? There is much confusion.
Before arguing particulars, let’s start all over again, from the beginning.
First consider: Marriage is a relationship that, as people of faith know, is integral to God’s plan for creation. Relationships, however, cannot be defined; they can only be described. How marriage is described is critical to how it is understood.
Viewing marriage from the perspective of the child is the only way that reveals its fullness, truth and beauty. From their perspective we can describe marriage in its totality that answers the question of “What is marriage in reality?
In reality, marriage unites a man and a woman with each other and ANY children born from their union.
What is the reality of marriage?
That’s what it is; that what it does. It is a fact that can only be recognized and never changed.
What is unique about this description of marriage is that it presumes everything that is essential to marriage. What is essential to marriage? sexual complementarity of the spouses, procreative acts, complementarity of parenting, etc. But this description includes much more. It includes what is particular to marriage: uniting children with their own mothers and fathers, irreplaceability, irrevocability, and non-substitutability. These are all concepts that are unfortunately seldom thought about in connection to marriage today.
This description takes into account the heartbreak of infertility with the use of the word “ANY” with regard to "children born from their union." Fruitfulness of the union is not essential to marriage, only the procreative act. Remember, not all married men and women have children, but every child has a mother and father — their own mother and father. That is reality.
To understand these particularities better, consider this description of marriage that reflects reality:
Marriage is when a man and a woman freely choose to make themselves irreplaceable to each other.
That is what prepares them to receive a new person, equal to them in value and dignity, from their union.
In reality, the child is irreplaceable to the mother and father. In reality, the mother and father are irreplaceable to the child. We know this to be true through our own desire to know and be loved by our own mother and father, even if we were deprived of that experience.
In reality, the free choice of the man and woman to marry starts the circle of irreplaceability that we call the family.
Young people can relate to this description of marriage even if they do not have married parents. They already know reality. They already know someone is missing in the family. This description clarifies the reality they already know, but it also provides a vision of the beauty and goodness of marriage that they will desire to seek for the sake of their own children.
See more at Witnessing Reality Marriage Reality, and Children and Children's Rights sections.