God is a God of order. God's order is magnificent and where you find it disrupted, you will find satan. If based on God's precepts and love, this relationship contains every lesson, every teaching, their children will need to be whole and to make upsociety. Society's cure lies within the spirit of the husband and wife toward each other. It is why satan wants with all his might to destroy the sacramental union.
Sin is the result of strong temptation.
Sin is the result of weakness. At least one party in a marriage has to sin to destroy a sacramental union. Whenever there is sin, there is satan. One of his favorite ploys is to divide husband and wife, then go after the children one by one. To split a husband and wife is to cause a societal explosion -chaos.