TheSacrament of Marriage joins a man and woman together in a loving covenant with God. A marriage in the Catholic Church must be permanent, exclusive and open to the possibility of having children and raising them within the Church. Catholics believe that marriage is a gift from God, as Jesus was united with his bride, the Church, and therefore husband and wife should grow together in love and trust.
Taken from The Faith Of The Catholic Church a CTS Publication
214.What is the grace of the Sacrament of Marriage?
The Sacrament of Marriage is a sign of the union between Christ and the Church. Spouses are given the grace to love each other with the love by which Christ has loved the Church. The grace of the Sacrament is intended to perfect the couple’s love to strengthen their insoluble union and to sanctify them in their journey to God.