This isn't the one you're thinking of, but it's similar:
w56 Marriage Obligations and Divorce
A man who divorces his wife on unadulterous grounds exposes her to adultery by a remarriage and also exposes himself in a like way. A man who marries a woman not divorced for adultery by herself or by her husband commits adultery with her, uniting himself with flesh that still belongs to another man.
And this quote from the same article is very interesting:
By the laws of states and nations today divorce is granted on a number of grounds. Persons who have lost or killed their love for their marriage mate try to grab hold of whatever legal grounds they can to break the marriage tie, such as mental cruelty, laziness, refusal of conjugal rights, drunkenness, insanity, incurable disease, desertion or abandonment, barrenness, sodomy, bestiality, criminality, incompatibility, change of one’s religion, and so on, besides adultery. But are all these legal grounds Scripturally right, valid for the Christian? Jesus Christ is Jehovah’s Counselor for us. The Jewish Pharisees once tested him with this question: "Is it lawful for a man to divorce his wife on every kind of grounds?" Jesus did not answer those questioners by referring to the Roman Caesar’s laws concerning divorce. He referred to the superior law of the Most High God and showed there is but one ground for divorce—adultery or moral unfaithfulness.
It's noteworthy that this article is also infamous for the following:
Sodomy (or the unnatural intercourse of one male with another male as with a female),Lesbianism (or the homosexual relations between women), and bestiality(or the unnatural sexual relations by man or woman with an animal)are not Scriptural grounds for divorce. They are filthy, they are unclean, and God’s law to Israel condemned to death those committing such misdeeds, thus drastically putting these out of God’s congregation. But such acts are not adultery with the opposite sex, making the unclean person one flesh with another of the opposite sex.
Such filthy things by a mate may make life unbearable for the clean married person and are grounds for separation only, though some courts grant a divorce on such grounds. Such separation does not free one to remarry and enter thus into adultery.
Further in the article it discusses the concept of why a spouses change in religious beliefs is not grounds for divorce:
Some law courts take as a ground for divorce the change in religion on the part of one’s mate. According to God and Christ this is not right. This law case assumes that, at marriage, both the husband and the wife were members of the same religious system, so that now the one’s change of religion creates a home difficulty on a most vital point. By adopting the new religion the one changing becomes an unbeliever toward the religion of the other mate. Though this may be a bitter experience for the mate that retains the former religion it is no real reason for him to separate from the other either by legal action or by mutual consent.
I'm speculating that this ruling was due to the growth in the JW religion at the time, and applied to non-JW spouses threatening to divorce their newly-converted-to-JW spouse. When the tables are turned, for example now when a JW couple has the dilemma of one of the partners leaving the JWs, apparently it is grounds for divorce, citing "absolute spiritual endangerment", although it does not free the couple to remarry per JW dogma.
Here's another article:
w69 3/15 p.177 Living Up to Your Decisions An unselfish and loving wife will always be very anxious to give the proper due to her husband, and to do the things that will make him happy and draw him closer to her. Paul said that the husband has charge over his wife; so even though she may not get the satisfaction, or need the satisfaction to the extent of her husband, yet her foremost thoughts should be the satisfaction of his passionate desires. Her delight and satisfaction will come in satisfying her husband.
Oh, I found something else:
w73 6/1 p.352 Questions from ReadersThe innocent mate may even have contributed toward the unfaithfulness of his or her marriage partner. If, for example, the wife has deliberately deprived her husband of the marital due, she bears a certain responsibility for what has happened. She is not altogether without blame from God’s standpoint, for the Bible admonishes: "Let the husband render to his wife her due; but let the wife also do likewise to her husband. . . . Do not be depriving each other of it, except by mutual consent for an appointed time, that you may devote time to prayer and may come together again, that Satan may not keep tempting you for your lack of self-regulation."—1 Cor. 7:3-5.