15 Men are wont to move a question concerning a third or fourth marriage, and even more numerous marriages than this. On which to make answer strictly, I dare neither to condemn any marriage, nor to take from these the shame of their great number. But, lest the brevity of this my answer may chance to displease any, I am prepared to listen to my reprover treating more fully. For perhaps he alleges some reason, why second marriages be not condemned, but third be condemned.
For I, as in the beginning of this discourse I gave warning, dare not to be more wise than it behooves to be wise. For who am I, that I should think that that must be defined which I see that the Apostle has not defined? For he says, “A woman is bound, so long as her husband lives.” He said not, her first; or, second; or, third; or, fourth; but, “A woman,” says he, “is bound, so long as her husband lives; but if her husband shall be dead, she is set free; let her be married to whom she will, only in the Lord: but she shall be more blessed, if she shall have so continued.”
I know not what can be added to, or taken from, this sentence, so far as relates to this matter. Next I hear Himself also, the Master and Lord of the Apostles and of us, answering the Sadducees, when they had proposed to Him a woman not once-married, or twice-married, but, if it can be said, seven-times married, whose wife she should be in the resurrection? For rebuking them, He says, “You do err, not knowing the Scriptures, nor the power of God. For in the resurrection they shall neither be married, nor marry wives; for they shall not begin to die, but shall be equal to the Angels of God.” Therefore He made mention of their resurrection, who shall rise again unto life, not who shall rise again unto punishment.
Therefore He might have said, You do err, knowing not the Scriptures, nor the power of God: for in that resurrection it will not be possible that there be those that were wives of many; and then added, that neither does any there marry. But neither, as we see, did He in this sentence show any sign of condemning her who was the wife of so many husbands. Wherefore neither dare I, contrary to the feeling of natural shame, say, that, when her husbands are dead, a woman marry as often as she will; nor dare I, out of my own heart, beside the authority of holy Scripture, condemn any number of marriages whatever. But, what I say to a widow, who has had one husband, this I say to every widow; you will be more blessed, if you shall have so continued.
Source: On the Good of Widowhood (New Advent)