"Conjugal love involves a totality, in which all the elements of the person enter - appeal of the body and instinct, power of feeling and affectivity, aspiration of the spirit and of will. It aims at a deeply personal unity, a unity that, beyond union in one flesh, leads to forming one heart and soul; it demands indissolubility and faithfulness in definitive mutual giving; and it is open to fertility. In a word it is a question of the normal characteristics of all natural conjugal love, but with a new significance which not only purifies and strengthens them, but raises them to the extent of making them the expression of specifically Christian values."
Source: Catechism of the Catholic Church (Vatican.va)