A Christian couple needs to have a good knowledge of the meaning of sex in God’s plan. Of all of the possible alternatives that God could have used to maintain and propagate the human race, he chose the physical and spiritual relationship of conjugal love. God wanted marriage to be the archetype of humanity and sexual intercourse to be the means of bringing new human life into the world.
In addition, he wanted this act to deepen the love between the spouses. This leads to the conclusion that God did not only invent sex; he gave it profound dignity and meaning. For this reason he established certain rules to help us live it correctly, in a way that will not cause conflict or suffering.
God wanted human beings to be both material and spiritual; a sort of beautiful synthesis of animal (purely material) and angel (purely spiritual).
When he gave human beings a body, he chose that we be sexually differentiated like the animals; however, our sexual life should be guided not by instinct, like animals, but by our soul, enlightened by intelligence, beautified by freedom, led by the will and lived in love.
In God’s plan, sexuality is something very sublime; this is why a married couple should never think that God is far way in the moment of their most intimate union. It is a holy and sanctifying act within marriage, specifically willed by God.
Conjugal love has a unique meaning. Other forms of love, such as friendship or family relationships between people of the same sex, don’t include the same physical complementarity. Sexual activity in its proper context–in marriage–and correctly understood in its spiritual and psychological aspects is one of the most noble and significant acts that a human being can engage in: it is the source of new life and a celebration of love. The virtue of chastity, rather than a renunciation of sex, means a correct use of sexuality.
Dr. Alphonse H. Clemens, Director of the Marriage Counseling Center at the Catholic University of America, says the following about the sexual act:
Raoul de Guchteneere, in "Judgment on Birth Control," states:
"It was recognized a long time ago that […] sexual relations produce profound psychological effects, especially in women. Once the sperm is absorbed by her body, it plays a dynamic role, promoting equilibrium. Generally speaking, the act of conjugal love results in relaxation, vigor, self-confidence, satisfaction, a general sense of well-being, a sensation of security and a disposition that is conducive to forgetting minor difficulties and tensions between the spouses.
It is not by chance that St. Paul recommended that Christian spouses "not deprive one another […] so that Satan may not tempt you." (1 Corinthians 7:5)
Refusing sex without a good reason may not only be an injustice towards the spouse, but also a danger of putting the spouse in danger of infidelity and risking the failure of the marriage. This shows that married couples should not stay separated for long, regardless of the reason, but especially not for ones of minor importance. Prolonged separation can create a stressful situation, particularly for the man. Some manage to endure this forced sexual abstinence by spiritual means, but not all are equally disposed.
Nonetheless, it is important to say that specialists have shown through their investigations that "other non-sexual factors are more important for marital happiness," as many couples overcome their problems and anxieties with the authenticity of their love.