As I stated in the previous post, The Church has taught through many centuries that the Primary End of Marriage is the Procreation and Education of Offspring.
This end is not just the cooperation of the spouses in bringing forth human lives into the world. It is this. But the fulness of human life is virtue and happiness, flourishing, relationships. By “education,” the Church means all these things. Thus, the primary end of marriage is that the spouses put themselves in the service of bringing new life into the world, human persons that will grow up to be kind, generous, courageous, magnanimous, creative, funny, original, obedient to God, etc. In short, the end is a contribution to the society of man under God. (This has implications for Catholics; Catholic spouses have as their primary end to bring up children in the communion and faith of the Mystical Body of Christ, which is the Catholic Church.)
There are other ends of marriage. The mutual help, affection, friendship that the spouses give to one another is the second end of marriage. Finally, the Church in her wisdom teaches that the third end of marriage is a “remedy for concupiscence.” Many people today are rather embarrassed or even naive about this end. Well, time to wake up and behold your humanity in its partly healed state. Concupiscence is still with us, despite baptism. The passions do not always follow what is reasonable. Hence, marriage provides a legitimate way in which these passions can be brought to order, as the spouses struggle to grow in virtue.
This is the Traditional teaching on marriage.