Concerning marriage, the Church speaks about the gift of human sexuality:
Sexuality is ordered to the conjugal love of man and woman. In marriage the physical intimacy of the spouses becomes a sign and pledge of spiritual communion. Marriage bonds between baptized persons are sanctified by the sacrament. (2360)*
Sexuality, by means of which man and woman give themselves to one another through the acts which are proper and exclusive to spouses, is not something simply biological, but concerns the innermost being of the human person as such. It is realized in a truly human way only if it is an integral part of the love by which a man and woman commit themselves totally to one another until death. (2361)
The Creator himself . . . established that in the [generative] function, spouses should experience pleasure and enjoyment of body and spirit. Therefore, the spouses do nothing evil in seeking this pleasure and enjoyment. They accept what the Creator has intended for them. At the same time, spouses should know how to keep themselves within the limits of just moderation. (2362)
This union achieves the twofold end of marriage, namely, faithful love and the transmission of life. Neither one can be separated from the other without damaging the couple's spiritual life and weakening the marriage itself.
This union requires fidelity; it stems from the spouses irrevocable consent to give themselves totally and definitively to one another (2364).
St. John Chrysostom suggests that young husbands should say to their wives: I have taken you in my arms, and I love you, and I prefer you to my life itself. For the present life is nothing, and my most ardent dream is to spend it with you in such a way that we may be assured of not being separated in the life reserved for us.... I place your love above all things, and nothing would be more bitter or painful to me than to be of a different mind than you. (2365)
The union of husband and wife also is fruitful. That is why the conjugal union expresses both unitive love and openness to new life. It is not selfish, that is, directed only to the spouses themselves. They are called by God to share in His creative power.
Part II will continue next week.
*Note: Numbers in brackets refer to the numbers assigned to paragraphs of The Catechism of the Catholic Church.