We are sometimes far too easily confused about what it means to practice charity. A refresher:
It is an outstanding manifestation of charity toward souls to omit nothing from the saving doctrine of Christ
(source: Humanae Vitae (July 25, 1968) | Paul VI)
In preserving intact the whole moral law of marriage, the Church is convinced that she is contributing to the creation of a truly human civilization. She urges man not to betray his personal responsibilities by putting all his faith in technical expedients. In this way she defends the dignity of husband and wife. This course of action shows that the Church, loyal to the example and teaching of the divine Savior, is sincere and unselfish in her regard for men whom she strives to help even now during this earthly pilgrimage “to share God’s life as sons of the living God, the Father of all men.”
(source: Humanae Vitae (July 25, 1968) | Paul VI)
And don’t miss the specific portions most applicable to our contemporary situation:
Therefore We base Our words on the first principles of a human and Christian doctrine of marriage when We are obliged once more to declare that the direct interruption of the generative process already begun and, above all, all direct abortion, even for therapeutic reasons, are to be absolutely excluded as lawful means of regulating the number of children. Equally to be condemned, as the magisterium of the Church has affirmed on many occasions, is direct sterilization, whether of the man or of the woman, whether permanent or temporary.
Similarly excluded is any action which either before, at the moment of, or after sexual intercourse, is specifically intended to prevent procreation—whether as an end or as a means.
Neither is it valid to argue, as a justification for sexual intercourse which is deliberately contraceptive, that a lesser evil is to be preferred to a greater one, or that such intercourse would merge with procreative acts of past and future to form a single entity, and so be qualified by exactly the same moral goodness as these. Though it is true that sometimes it is lawful to tolerate a lesser moral evil in order to avoid a greater evil or in order to promote a greater good,” it is never lawful, even for the gravest reasons, to do evil that good may come of it–in other words, to intend directly something which of its very nature contradicts the moral order, and which must therefore be judged unworthy of man, even though the intention is to protect or promote the welfare of an individual, of a family or of society in general. Consequently, it is a serious error to think that a whole married life of otherwise normal relations can justify sexual intercourse which is deliberately contraceptive and so intrinsically wrong.
(source: Humanae Vitae (July 25, 1968) | Paul VI, emphasis added)