If a man or a woman marries only to satisfy the sins of the flesh, I pity their poor children.
The quieting of concupiscence (concupiscentiæ sedatio
, as Pope Pius XI descriptively calls it in Casti Connubii
) is a secondary end of marriage.
Instead, a couple who plans to marry should seek to purify themselves and live a life of purity and holiness so that together they can enter the Kingdom of Heaven.
If that's their goal, then why marry? Such an end can be achieved safer and more readily in the religious than the married state.
The primary end of marriage is the procreation and education of children, not the sanctification of the spouses.