I don't see Marriage as a contract.

I see Marriage as a Holy Sacrament.

Although the Church realized from the first the complete sacramentality of Christian marriage, yet for a time there was some uncertainty as to what in the marriage contract is the real essence of the sacrament; as to its matter and form, and its minister. From the earliest times this fundamental proposition has been upheld: Matrimonium facit consensus, i.e. Marriage is contracted through the mutual, expressed consent. Therein is contained implicitly the doctrine that the persons contracting marriage are themselves the agents or ministers of the sacrament. However, it has been likewise emphasized that marriage must be contracted with the blessing of the priest and the approbation of the Church, for otherwise it would be a source not of Divine grace, but of malediction. Hence it might easily be inferred that the sacerdotal blessing is the grace-giving element, or form of the sacrament, and that the priest is the minister. But this is a false conclusion. The first theologian to designate clearly and distinctly the priest as the minister of the Sacrament and his blessing as the sacramental form was apparently Melchior Canus (d. 1560). In his well-known work, "De locis theologicis", VIII, v, he sets forth the following propositions:

It is, indeed, a common opinion of the schools, but not their certain and settled doctrine, that a marriage contracted without a priest is a true and real sacrament;
the controversies on this point do not affect matters of faith and religion;
it would be erroneous to state that all theologians of the Catholic school defended that opinion.