Nicene and Post-Nicene Fathers, Ser. II, Vol. XIV:
The Canons of the Councils of Ancyra, Gangra, Neocæsarea, Antioch and Laodicea, which Canons were Accepted and Received by the Ecumenical Synods.: Canon XIX

Canon XIX.

If any persons who profess virginity shall disregard their profession, let them fulfil the term of digamists.  And, moreover, we prohibit women who are virgins from living with men as sisters.

Notes.

Ancient Epitome of Canon XIX.

Whoever has professed virginity and afterwards annuls it, let him be cut off for four years.  And virgins shall not go 118 to any as to brothers.

Hammond.

According to some of the ancient canons digamists were to be suspended from communion for one or two years, though Beveridge and others doubt whether the rule was not meant to apply to such marriages only as were contracted before a former one was dissolved.  Bingham thinks that it was intended to discountenance marrying after an unlawful divorce.  (Ant., Bk. xv, c. iv., § 18.) 119

Hefele.

The first part of this canon regards all young persons—men as well as women—who have taken a vow of virginity, and who, having thus, so to speak, betrothed themselves to God are guilty of a quasi digamy in violating that promise.  They must therefore incur the punishment of digamy (successiva) which, according to St. Basil the Great, consisted of one year’s seclusion.

This canon is found in Gratian’s Decretum (P. II., Causa xxvii., Q. i., c. xxiv.) as follows:  “As many as have professed virginity and have broken their vow and contemned their profession shall be treated as digamists, that is as those who have contracted a second marriage.”

Footnotes

Aristenus understands this to mean to “live with,” using the verb συναναστρέφεσθαι.

This view of Bingham’s would seem to be untenable, since the penance would have been for adultery not for digamy had the former marriage still been in force.