Most Catholics marry and have children. Children are a gift from God. Love in marriage grows by depending upon the Providence of God in keeping open every conjugal act to the possibility of having children. Knowing that each conjugal act might initiate a life adds to the drama of expecting to have one. It creates a welcoming frame of mind in the couple towards the child contrasted to a grudging attitude in those who tried to prevent the birth by contraception.
Celibacy demands self-control for the sake of the other.
Celibacy practiced for the sake of the Kingdom of God reminds us that love does not depend on sexual relations. The other is not seen as an object, but as someone from whom we forbear. Thus celibacy practiced for the sake of the kingdom manifests the love that the children of God will practice in heaven. St. Paul suggested that it is good for married couples to occasionally restrain from sexual relations. While the physical union of husband and wife draws them closer, so too periodical abstention from sexual relations reinforced with prayer can unite them more closely.