Question: "Are married couples required to abstain from sex during the fasts?"
The short answer is "no." But a longer answer is necessary here.
It is a pious custom for married couples to abstain from sex during the fasts, and when this is done by mutual consent, that is a good and laudable thing. However, the key word in the question is "required," and something that must be by mutual consent cannot therefore be required.
St. Paul addresses this question directly:
"Now concerning the things whereof ye wrote unto me: It is good for a man not to touch a woman. Nevertheless, to avoid fornication, let every man have his own wife, and let every woman have her own husband. Let the husband render unto the wife due benevolence: and likewise also the wife unto the husband. The wife hath not power of her own body, but the husband: and likewise also the husband hath not power of his own body, but the wife. Defraud ye not one the other, except it be with consent for a time, that ye may give yourselves to fasting and prayer; and come together again, that Satan tempt you not for your incontinency. But I speak this by permission, and not of commandment" (1 Corinthians 7:1-6).St. John Chrysostom comments on this as follows:
"The wife hath not power over her own body;” but is both the slave and the master of the husband. And if you decline the service which is due, you have offended God. But if thou wish to withdraw thyself, it must be with the husband’s permission, though it be but a for short time. For this is why he calls the matter a debt, to shew that no one is master of himself but that they are servants to each other. When therefore thou seest an harlot tempting thee, say, “My body is not mine, but my wife’s.” The same also let the woman say to those who would undermine her chastity, “My body is not mine, but my husband’s.” Now if neither husband nor wife hath power even over their own body, much less have they over their property. Hear ye, all that have husbands and all that have wives: that if you must not count your body your own, much less your money" (Homily 19 on 1st Corinthians).And specifically on the meaning St. Paul's admonition: "Defraud ye not one the other, except it be with consent for a time," St. John says:
"What then can this mean? “Let not the wife,” says he, “exercise continence [i.e. abstain from marital relations], if the husband be unwilling; nor yet the husband without the wife’s consent.” Why so? Because great evils spring from this sort of continence. For adulteries and fornications and the ruin of families have often arisen from hence. For if when men have their own wives they commit fornication, much more if you defraud them of this consolation. And well says he, “Defraud not; fraud” here, and “debt” above, that he might shew the strictness of the right of dominion in question. For that one should practice continence against the will of the other is “defrauding;” but not so, with the other’s consent: any more than I count myself defrauded, if after persuading me you take away any thing of mine. Since only he defrauds who takes against another’s will and by force. A thing which many women do, working sin rather than righteousness, and thereby becoming accountable for the husband’s uncleanness, and rending all asunder. Whereas they should value concord above all things, since this is more important than all beside.A husband and a wife have a responsibility to serve one another, and to help each other on the path of salvation. If depriving your spouse of marital relations causes them to sin, you are responsible for having caused them this temptation.
We will, if you please, consider it with a view to actual cases. Thus, suppose a wife and husband, and let the wife be continent, without consent of her husband; well then, if hereupon he commit fornication, or though abstaining from fornication fret and grow restless and be heated and quarrel and give all kind of trouble to his wife; where is all the gain of the fasting and the continence, a breach being made in love? There is none. For what strange reproaches, how much trouble, how great a war must of course arise! since when in an house man and wife are at variance, the house will be no better off than a ship in a storm when the master is upon ill terms with the man at the head. Wherefore he saith, “Defraud not one another, unless it be by consent for a season, that ye may give yourselves unto prayer.” It is prayer with unusual earnestness which he here means. For if he is forbidding those who have intercourse with one another to pray, how could “pray without ceasing” have any place? It is possible then to live with a wife and yet give heed unto prayer. But by continence prayer is made more perfect. For he did not say merely, “That ye may pray;” but, “That ye may give yourselves unto it;” as though what he speaks of might cause not uncleanness but much occupation.
“And may be together again, that Satan tempt you not.” Thus lest it should seem to be a matter of express enactment, he adds the reason. And what is it? “That Satan tempt you not.” And that you may understand that it is not the devil only who causeth this crime, I mean adultery, he adds, “because of your incontinency” (Homily 19 on 1st Corinthians).
In this regard, Origen wrote:
"You have given up your wife, to whom you are bound. This is a big step you have taken. You are not abusing here, you say, but claiming that you can be chaste and live more purely. But look how your poor wife is being destroyed as a result, because she is unable to endure your purity! You should sleep with your wife, not for your sake, but for hers. (Commentary on 1 Corinthians 3.33.23-25, quoted in Ancient Christian Commentary on Scripture: New Testament, Vol. VII, Gerald Bray, ed. (Downers Grove, IL: Intervasity Press, 1999) p. 59f).St. Augustine wrote a letter to a woman named Eudicia on this issue, and advised her, based on St. Paul's words as follows:
"According to this, if he had wished to practice continence but you had not, he would have been obliged to give in to you, and God would have given him credit for continence for not refusing intercourse out of consideration for your weakness, but not his own, in order to prevent you from committing adultery. How much better would it have been for you, for whom subjection was more appropriate, to yield to his will in rendering him the debt, since God would have taken account of your intention to observe continence, which you gave up in order to save your husband from destruction" (Letter 262 to Eudicia, quoted in Ancient Christian Commentary on Scripture: New Testament, Vol. VII, Gerald Bray, ed. (Downers Grove, IL: Intervasity Press, 1999) p. 62).So in summary, it is good to fast from marital relations for a time, by mutual consent, but it is positively sinful to insist upon it, if your spouse does not consent. And according to St. Augustine, when such a spouse do not refuse their husband or wife, they have both the virtue of having had good intentions, and also of showing due love and consideration for their spouse.
Finally, it worth considering the wise words of Fr. Alexander Lebedeff:
"Not long after we were married, my wife and I (I was a third year Seminarian at Jordanville then), were invited to have lunch by one of the old Russian couples that lived in the so-called "Russian village" about a mile from the monastery. We gladly accepted (we were so poor, we were subsisting mainly on macaroni, so any invitation "out" was deeply appreciated). After a wonderful Russian meal, the old "babushka" of the house took us over to the side and conspiratorily whispered: "I know you're recently married, but you do know, of course, the Church rules on when you can, and when you can't?"
It was pretty clear what she was talking about, so we just politely nodded.
She went on: "Well, you can't do it on Tuesday, because that's the eve of a fast day; you can't do it on Wednesday, because it's a fast day; you can't do it on Thursday, because that's the eve of a fast day, also; you obviously can't do it on Friday, because that's a fast day, too; you can't do it on Saturday, because that's the eve of a Feast Day, and you can't do it on Sunday, because that's a Feast Day."
"What about Monday?" I asked.
"Well, you can't do it on Monday, either, because of an old pious custom, since Monday is dedicated to the Bodiless Powers, the Angels, who are an example of purity--and it's also a fast day among monastics."
I asked the venerable Babushka, "And you followed these rules strictly when you were young and just married?"
"Oh, no," she replied, "We were young and foolish, and didn't know any better. . . "
The point of this story is that old babushkas are the first to point out restrictions that do not at all exist according to the Church. The scriptural admonition is for married couples *not* to deny each other sexual relations, except by mutual consent for the purpose of prayer and fasting.
Abstinence from sexual relations (by mutual consent) is certainly appropriate the evening before receiving the Holy Sacraments, and during the day that one receives them. It is certainly *not* an absolute "requirement" of the Church to abstain on all fast days (and on the eves of fast days), or during the 11 days after the Nativity when marriages are not permitted.
The Russian Church in the 13th century issued guidelines for married clergy on these issues, and they included as days of mandatory abstinence only the first and last week of Great Lent, the two weeks of Dormition Lent, and Wednesdays and Fridays during Nativity Lent and the Lent of the Holy Apostles.
The married state is blessed and the marriage bed is undefiled. The Holy Church in protecting the sanctity of marriage and the well-being of the spouses, as well as encouraging procreation and the raising of "fair children" has no interest in creating artificial impediments to preclude spouses from "rejoicing in one another."
If anyone wishes individual guidance on these matters, they should, of course, consult with their Spiritual Father."