Tertullian (Rome, 160 - 220),
To His Wife,
Bk. 2:7, ML 1, 1299
If, then, a marriage of this kind (faithful with unfaithful) is
approved by God, why will it not also be a successful marriage,
in spite of difficulties and anxieties and obstacles and
defilements, since it already enjoys the patronage of Divine
grace, at least in part?