Thomas Aquinas

“ It would seem that the wife may not take another husband, if her husband has entered religion before the consummation of the marriage. For that which is consistent with marriage does not dissolve the marriage tie. Now the marriage tie still remains between those who equally take religious vows. Therefore by the fact that one enters religion, the other is not freed from the marriage tie. But as long as she remains tied to one by marriage, she cannot marry another. ”

“ Therefore one of them cannot take a religious vow without the other's consent.
I answer that, No one can make an offering to God of what belongs to another. Wherefore since by a consummated marriage the husband's body already belongs to his wife, he cannot by a vow of continence offer it to God without her consent.
Reply to Objection 1: Human law considers marriage merely as fulfilling an office of nature: whereas the Divine law considers it as a sacrament, by reason of which it is altogether indissoluble. ”

“ Further, after entering religion and before making his profession the husband can return to the world. If then the wife can marry again when her husband enters religion, he also can marry again when he returns to the world: which is absurd. ”