One of the best descriptions of sacramental marriage we have come across is found in the controversial eighth chapter of Amoris Laetita in ¶292:
"Christian marriage, as a reflection of the union between Christ and his Church, is fully realized in the union between a man and a woman who give themselves to each other in a free, faithful and exclusive love, who belong to each other until death, are open to the transmission of life, and are consecrated by the sacrament, which grants them the grace to become a domestic church and a leaven of new life for society."