The matrimonial covenant, by which a man and a woman establish between themselves a partnership of the whole of life, is by its nature ordered toward the good of the spouses and the procreation and education of offspring; this covenant between baptized persons has been raised by Christ the Lord to the dignity of a sacrament.
For more information on church doctrine concerning the sacrament of Matrimony, the Office for the Catechism maintains an online Catechism.
News Articles:
"Bringing Your Marriage Into the Church"
by Msgr. Joseph M. Champlin
"Sacrament of Marriage: Sign of Faithful Love"
by Thomas Richstatter, O.F.M., Th.D.
"The U.S. Bishops’ Between Man and Woman: Questions and Answers About Marriage and Same-Sex Unions"
Between Man and Woman: Questions and Answers About Marriage and Same-Sex Unions in condensed form
"Marriage: Forgiving and Being Forgiven"
by Carol Luebering
Update Your Faith:
What does the Sacrament of Marriage reveal to us about God?