Whether it may have been lawful by dispensation to put away a wife?

Objections

Objection 1 : It seems that it could not be lawful by dispensation to put away a wife. For in marriage anything that is opposed to the good of the offspring is against the first precepts of the natural law, which admit of no dispensation. Now such is the putting away of a wife, as stated above (Article [1]). Therefore, etc.
Objection 2 : Further, a concubine differs from a wife especially in the fact that she is not inseparably united. But by no dispensation could a man have a concubine. Therefore by no dispensation could he put his wife away.
Objection 3 : Further, men are as fit to receive a dispensation now as of old. But now a man cannot receive a dispensation to divorce his wife. Neither, therefore, could he in olden times.