72. The sacrament of marriage is not a social convention, an empty ritual or merely the outward sign of a commitment. The sacrament is a gift given for the sanctification and salvation of the spouses, since “their mutual belonging is a real representation, through the sacramental sign, of the same relationship between Christ and the Church. The married couple are therefore a permanent reminder for the Church of what took place on the cross; they are for one another and for their children witnesses of the salvation in which they share through the sacrament”.(Familiaris Consortio 13) Marriage is a vocation, inasmuch as it is a response to a specific call to experience conjugal love as an imperfect sign of the love between Christ and the Church. Consequently, the decision to marry and to have a family ought to be the fruit of a process of vocational discernment.
Marriage is many things. Sometimes people fail to take advantage of their opportunities. Like the Eucharist, the marriage exists to give glory to God and for the sanctification of the faithful. I think pastors and others who assist couples in the preparation of marriage might be missing this point of vocational discernment.
For your reference, remember that Amoris Laetitia is online here.