Just gonna leave these here...
Canon 10 of the Council of Laodicea
The members of the Church shall not indiscriminately marry their children to heretics.
Canon 31 of the Council of Laodicea
It is riot lawful to make marriages with all heretics, nor to give our sons and daughters to them; but rather to take of them, if they promise to become Christians.
Canon 21 of the 419 Council of Carthage
Likewise it seemed good that the sons of clergymen should not be joined in matrimony with gentiles and heretics.
Canon 14 of the Council of Chalcedon
Since in certain provinces it is permitted to the readers and singers to marry, the holy Synod has decreed that it shall not be lawful for any of them to take a wife that is heterodox. But those who have already begotten children of such a marriage, if they have already had their children baptized among the heretics, must bring them into the communion of the Catholic Church; but if they have not had them baptized, they may not hereafter baptize them among heretics, nor give them in marriage to a heretic, or a Jew, or a heathen, unless the person marrying the orthodox child shall promise to come over to the orthodox faith. And if any one shall transgress this decree of the holy synod, let him be subjected to canonical censure.
Canon 72 of the Council of Trullo
An orthodox man is not permitted to marry an heretical woman, nor an orthodox woman to be joined to an heretical man. But if anything of this kind appear to have been done by any to consider the marriage null, and that the marriage be dissolved. For it is not fitting to mingle together what should not be mingled, nor is it right that the sheep be joined with the wolf, nor the lot of sinners with the portion of Christ. But if any one shall transgress the things which we have decreed let him be cut off. But if any who up to this time are unbelievers and are not yet numbered in the flock of the orthodox have contracted lawful marriage between themselves, and if then, one choosing the right and coming to the light of truth and the other remaining still detained by the bond of error and not willing to behold with steady eye the divine rays, the unbelieving woman is pleased to cohabit with the believing man, or the unbelieving man with the believing woman, let them not be separated, according to the divine Apostle, “for the unbelieving husband is sanctified by the wife, and the unbelieving wife by her husband.”
Economy is necessary in many situations, but we can never forget that it is just that: economy!