From a Catholic perspective, marriage is a permanent and exclusive commitment between a man and a woman, who freely give themselves to each other in love and in so doing commit themselves to love and care for any children that may arise from their mutual love. Commitment, intimacy and passion vitalize and nurture covenanted love (Genovesi, 1996). Sexual intimacy is a sign of fully committed love. Outside the context of marriage, genital intimacy, however well intended, is not an expression of total self-giving. Marriage is also a public commitment. The two partners freely choose to enter into this partnership, this covenant. They say 'yes' to each other, to being there for each other and to working together to make God's creative love present in the world. They do this through their active participation in the community as committed partners and through bringing about new life through sexual intercourse. The Catholic perspective on marriage is that it should be treated as something permanent and exclusive in which divorce and extra-marital affairs have no place. Public commitment to a permanent and exclusive partnership of mutual co-operation and self-giving love provides the institutional and community basis for the trust necessary for the married couple to truly open themselves to each other. They are able to give themselves wholly to each other in the knowledge that there is a community who will support them in their decision when times are hard and assist them in the raising of their children.

Marriage is also a Sacrament. In a unique way marriage makes Christ visible in the world through the power of the Holy Spirit. The Second Vatican Council's 1965 Pastoral Constitution of the Church in the Modern World, Gaudium et Spes, explains it like this: For as God of old made Himself present to His people through a covenant of love and fidelity, so now the Savior of men and the Spouse of the Church comes into the lives of married Christians through the sacrament of matrimony. He abides with them thereafter so that just as He loved the Church and handed Himself over on her behalf, the spouses may love each other with perpetual fidelity through mutual self-bestowal. Authentic married love is caught up into divine love and is governed and enriched by Christ's redeeming power and the saving activity of the Church, so that this love may lead the spouses to God with powerful effect and may aid and strengthen them in sublime office of being a father or a mother. For this reason Christian spouses have a special sacrament by which they are fortified and receive a kind of consecration in the duties and dignity of their state. By virtue of this sacrament, as spouses fulfil their conjugal and family obligation, they are penetrated with the spirit of Christ, which suffuses their whole lives with faith, hope and charity. Thus they increasingly advance the perfection of their own personalities, as well as their mutual sanctification, and hence contribute jointly to the glory of God (Gaudium et Spes, para. 48).

In light of this ideal of marriage the separation of a married couple is always seen as something undesirable. People who have been through such a separation know from experience how undesirable separation is. No one should enter into marriage expecting its break down and the consequent separation of the couple. Indeed, thinking like that may even call the validity of the marriage into question. Most people, when they get married, really do believe, or at least hope, that they will live with and love each other for the rest of their lives. This is why, when, for many reasons, things don't work out it is regarded as tragic. Of course, at the time of separation, the separation may indeed be desired and necessary as in cases of domestic violence or infidelity. The Catholic perspective, whilst upholding the ideal on the one hand, nonetheless accepts human failings on the other. In such cases, where, despite support of the community separation is necessary, the Catechism of the Catholic Church states: 'If civil divorce remains the only possible way of ensuring certain legal rights, the care of the children, or the protection of inheritance, it can be tolerated and does not constitute a moral offense.' (CCC Article 2383)