But there is hardly anything more serious than to be joined in marriage to a stranger (i.e., to an unbeliever), where the instigations both of lustful appetite and of disharmony and the shameful crimes of sacrilege are welded together. For if marriage itself needs to be sanctified by the priestly veil and blessing, how is it possible to speak of a marriage where there is no agreement in faith?– St. Ambrose of Milan (+397) 

…The husband and wife must lay virtue, and not passion, as the foundation of their love, that is, when the husband sees any fault in his wife, he must nudge her meekly, and the wife must submit to her husband in this. Likewise when a wife sees some fault in her husband, she must exhort him, and he is obliged to hear her. In this manner their love will be faithful and unbroken, and thereby having mutually composed their happiness, they shall take pleasure in the virtue. St. Tikhon of Zadonsk (+1783) 

Ponder the truth of Christian marriage: man and wife are one flesh! Does it not follow that they must share all their possessions? And yet you two haggle over this property! And why? Because of words!       St. Macarius of Optina (+1860)