Roman Catechism 22.44

Chapter 22 — Part II: The Sacraments — Matrimony

Section 44. In the second place, if marriage could be dissolved by divorce, married persons would hardly ever be without causes of disunion, which would be daily supplied by the old enemy of peace and purity; while, on the contrary, now that the faithful must remember that even though separated as to bed and board, they remain none the less bound by the bond of marriage with no hope of marrying another, they are by this very fact rendered less prone to strife and discord. And even if it sometimes happens that husband and wife become separated, and are unable to bear the want of their partnership any longer, they are easily reconciled by friends and return to their common life.