Now that we have specified the Primary End of marriage, we must add nuance.
Pius XI, Casti connubii, art. 24, and the Roman Catechism, p. 343f, assist us here. For they each speak of the very loving society, the friendship, the rational (and charitable) affection of male and female, as constituting a primary reason an individual might seek the married life. The Roman Catechism uses the term causa. The RC teaches that there are three causae why a person might piously and religiously suggest to himself to get married: first, the very beauty of lifelong companionship with one of the opposite sex; second, children; third, a remedy for concupiscence. Pius XI cites the RC and uses the terms causa et ratio.
Neither Pius XI nor the RC describe these causae as ends. (Thus, the translation in the TAN edition of the RC is misleading.) It seems safe to conclude that both Pius XI and the RC are suggesting subjective motives, the human reasons that humans have for getting married. If that is so, this is not an alternative list of “ends” in competition with the first list. In fact, as I stated above in Part 22, the holier the person the more his subjective motives mirror the objective ends founded by God.
Vatican II and John Paul II draw out these very insights of the RC and Pius XI.
That the Roman Catechism and Pius XI already anticipate what John Paul does shows that we are not dealing with a “post-conciliar” idea foreign to the Tradition. John Paul did not cause a “rupture”. The Church has always recognized a complexity in this matter. Not confusion. But certainly complexity. One might also take a glance at Thomas Aquinas, Summa theologiae, Supplement, q. 49, art. 3. The Supplement is taken from his Sentences Commentary.
But we can easily recognize the obviousness of this complexity ourselves.
Just think, when a man first proposes to himself, “She is wonderful, I want to be with her some more.” When he says that to himself, his thought is not, “I have a duty to procreate. Therefore, I should seek a partner. Perhaps she would do.” Hardly likely.
His whole life, he has been living humanly. And God, in his gentle providence, draws people to marriage in a manner befitting their human character. God draws people together through the natural affection of man for woman, of woman for man. Proposing to be with one another is what the man and woman say to themselves when they are thinking of marriage. You might call this a kind of “subjective end” or motivation.