Catholics are Christians, so “Catholic marriage vs Christian marriage” is not a comparison between Christianity and something outside it. A clearer comparison is between Catholic teaching on marriage and the teachings or practices found in other Christian traditions.
Catholic understanding of marriage
The Catholic Church teaches that marriage is a covenant between a man and a woman ordered toward the good of the spouses and the procreation and education of children. When two baptized persons enter a valid marriage, Catholic teaching regards the marriage as a sacrament.
Consent is essential. The spouses themselves give consent, while the Church receives that consent according to its canonical form unless a dispensation applies.
Other Christian approaches
Orthodox, Anglican, Lutheran, Methodist, Reformed, Baptist, Pentecostal, and evangelical churches all affirm marriage, but they do not describe it in exactly the same way. Eastern Orthodox churches treat marriage as a sacramental mystery. Many Protestant churches regard marriage as a sacred covenant or institution but do not count it among the sacraments in the same sense as Catholicism.
Wedding ceremony
A Catholic wedding between two Catholics normally takes place according to Catholic canonical requirements. A Mass may be celebrated when appropriate. In many Protestant churches, wedding services center on scripture, vows, prayer, and a pastoral blessing. Orthodox weddings use a distinctive rite that includes betrothal and crowning.
Divorce and remarriage
The Catholic Church teaches the indissolubility of a valid sacramental marriage. Civil divorce may sometimes be tolerated for legal protection or other serious reasons, but it does not by itself dissolve a valid marriage in Catholic teaching.
A declaration of nullity, often called an annulment, is different from divorce. It is a judgment that a valid marriage was not established from the beginning because an essential requirement was absent.
Other Christian churches differ. Some permit divorce and remarriage under particular circumstances. Eastern Orthodox churches may allow a second marriage in certain cases under pastoral discipline. Protestant policies range from restrictive to more permissive depending on denomination and local church practice.
Interchurch and interfaith marriage
Catholic law distinguishes between marriage with another baptized Christian and marriage with an unbaptized person. Permission or dispensation may be required. Other churches also have their own rules about weddings involving people from different denominations or religions.
Contraception and family life
Catholic teaching rejects artificial contraception and emphasizes openness to life while permitting natural methods of regulating births for serious reasons. Many Protestant churches allow contraception within marriage. Orthodox pastoral practice can vary by jurisdiction and spiritual guidance.
What most Christian traditions share
Despite substantial differences, Christian churches commonly emphasize fidelity, mutual responsibility, care for children, prayer, and the moral seriousness of marriage. The main differences concern sacramental theology, divorce and remarriage, sexual ethics, and church law.
Because “Christian marriage” covers many traditions, the most accurate comparison is always between Catholic teaching and a named church or denomination.