476. XII. THAT WHILE THIS CONCUBINAGE CONTINUES, ACTUAL CONJUNCTION WITH THE WIFE IS NOT LAWFUL. The reason is because in such case conjugial love, which in itself is spiritual, chaste, pure and holy, becomes natural, is contaminated and worn out, and thus perishes. Wherefore, that this love may be preserved, it is expedient that concubinage from really weighty causes (nos. 472, 473) be with one only and not with two at the same time.