Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Synods of Sardica, Carthage, Constantinople, and Carthage Under St. Cyprian, Which Canons Were Received by the Council in Trullo and Ratified by II. Nice.: Canon CII

Canon CII.  (Greek cv.)

Of those who put away their wives or husbands, that so they remain.

It seemed good that according to evangelical and apostolical discipline a man who had been put away from his wife, and a woman put away from her husband should not be married to another, but so should remain, or else be reconciled the one to the other; p. 494 but if they spurn this law, they shall be forced to do penance, covering which case we must petition that an imperial law be promulgated.

Notes.

Ancient Epitome of Canon CII.

Married people who are loosed must remain unmarried or else be reconciled, otherwise they shall be forced to do penance.

This canon is Canon viij. of Carthage, a.d. 407, and is found in the Corpus Juris Canonici, Gratian’s Decretum, P. II., Causa xxxij., Quæst. vij., can. v.