Bede the Venerable — as excerpted in the Catena Aurea on Mark 10:1-12

“(ubi sup.) What therefore God hath conjoined by making one flesh of a man and a woman, that man cannot separate, but God alone. Man separates, when we dismiss the first wife because we desire a second; but it is God who separates, when by common consent, for the sake of serving God, we so have wives as though we had none.n”