XXI.  If a man living with a wife is not satisfied with his marriage and falls into fornication, I account him a fornicator, and prolong his period of punishment.  Nevertheless, we have no canon subjecting him to the charge of adultery, if the sin be committed against an unmarried woman.  For the adulteress, it is said, “being polluted shall be polluted,” Jer. iii. 1. and she shall not return to her husband:  and “He that keepeth an adulteress is a fool and impious.” Prov. xviii. 22, LXX.  He, however, who has committed fornication is not to be cut off from the society of his own wife.  So the wife will receive the husband on his return from fornication, but the husband will expel the polluted woman from his house.  The argument here is not easy, but the custom has so obtained. “Non solus Basilius hanc consuetudinem secutus.  Auctor constitutionum apostolicarum sic loquitur lib. vi. cap. 14:  Qui corruptam retinet, naturæ legem violat:  quando quidem qui retinet adulteram, stultus est et impius.  Abscinde enim eam, inquit, a carnibus tuis.  Nam adjutrix non est, sed insidiatrix, quæ mentem ad alium declinarit.  Canon 8, Neocæsariensis laicis, quorum uxores adulterii convictæ, aditum ad ministerium ecclesiasticum claudit; clericis depositionis pœnam irrogat, si adulteram nolint dimittere.  Canon 65 Eliberitanus sic habet:  Si cujus clerici uxor fuerit mæchata, et scierit eam maritus suus mæchari, et non eam statim projecerit, nec in fine accipiat communionem.  Hermas lib. i, c. 2, adulteram ejici jubet, sed tamen pœnitentem recipi.  S. Augustinus adulterium legitimam esse dimittendi causam pronuntiat, sed non necessariam, lib. ii. De Adulter. nuptiis, cap. 5, n. 13.”