The marital unity of man and woman is both spiritual, making a new spiritual relationship (Matthew 19:5), and physical, becoming one flesh
(Matthew 19:6): uniting them not only in interests, but also in authority over each other’s bodies (1 Corinthians 7:4). However, this does not mean that individuality vanishes, just as it does not vanish when we become one with Christ. Marriage is the strongest bond between two people: a friendship in which love reigns in every sphere (both spiritual and physical). Ultimately the sexual union makes the two one flesh (1 Corinthians 6:16). It is God himself who joins a man and a woman together, sealing the new relationship.
The unity of man and woman in marriage is both spiritual in that they form a new spiritual relationship (Matthew 19:5), but also physical in that they become one flesh
(Matthew 19:6). This means that they are one in the sense that not only do their interests become one, but they also have authority over each other’s bodies (1 Corinthians 7:4). This does not mean that individuality disappears, however, just like it does not disappear when we become one with Christ. Marriage is the strongest and most intimate bond of friendship between two human beings—a friendship in which love reigns in every sphere (both spiritual and physical). Ultimately it is the sexual act of love through which the two become one flesh (1 Corinthians 6:16). This highlights how it is God himself who joins a man and a woman together, sealing the new relationship. This principle, of course, applies not only to Adam and Eve but to every marriage.1
6 Ainsi ils ne sont plus deux, mais ils sont une seule chair. Que l'homme donc ne sépare pas ce que Dieu a joint.