90 To revert again to the expression of Our predecessor, it is hardly necessary to point out what an amount of good is involved in the absolute indissolubility of wedlock and what a train of evils follows upon divorce. Whenever the marriage bond remains intact, then we find marriages contracted with a sense of safety and security, while, when separations are considered and the dangers of divorce are present, the marriage contract itself becomes insecure, or at least gives ground for anxiety and surprises. On the one hand we see a wonderful strengthening of goodwill and cooperation in the daily life of husband and wife, while, on the other, both of these are miserably weakened by the presence of a facility for divorce. Here we have at a very opportune moment a source of help by which both parties are enabled to preserve their purity and loyalty; there we find harmful inducements to unfaithfulness. On this side we find the birth of children and their tuition and upbringing effectively promoted, many avenues of discord closed amongst families and relations, and the beginnings of rivalry and jealousy easily suppressed; on that, very great obstacles to the birth and rearing of children and their education, and many occasions of quarrels, and seeds of jealousy sown everywhere. Finally, but especially, the dignity and position of women in civil and domestic society is reinstated by the former; while by the latter it is shamefully lowered and the danger is incurred "of their being considered outcasts, slaves of the lust of men."
Source: Casti Connubii (Vatican.va)