Anthropological foundations of the difference between marriage and “de facto” unions

(19) Marriage is based on some well-defined anthropological foundations which distinguish it from other kinds of union and which—beyond the realm of concrete action and what is “factual”—root it in the very essence of the person of the woman or the man.

These presuppositions include: equality between men and women, for both are persons equally [28][28] (although in different ways); the complementary character of the sexes[29][29] from which comes their natural inclination toward the generation of children; the possibility to love one another precisely because they are sexually different and complementary in such a way that “this love is expressed and perfected uniquely through the acts proper to marriage”;[30][30] the possibility—of freedom—to set up a stable and definitive relationship, i.e., one that is due in justice;[31][31] and, lastly, the social dimension of the conjugal and family condition which constitutes the first context of education and openness to society through family relations (which contribute to shaping the identity of the human person).[32][32]