Sexual relations: Prohibition of thinking of another person

This is a continuation of the discussion of chanifa - or tocho k'baro or echad b'peh  echad b'lev - the need to have consistency or integrity of inner thoughts and emotions with external behavior or speech. It is prohibited to deliberately think about another person during sexual relations or even to not know who the other person is - whether deliberately or by accident. The case of Yaakov being with Leah presents a significant problem for this. Chazal say that not having attention directed to the other person during sexual relations results in a child which is like a mamzer.

Lehoros Nosson (2:88):The poskim don't mention this and it obviously is not the halacha. Even though it is explicitly mentioned by our Sages (Pesachim 112a)A person should not cook in a pot that someone else has already used. That means that a person should not marry a divorced woman while her ex-husband is still alive. For a master said when a divorced man marries a divorced woman there are four minds in the bed. [Alternatively this applies even to marrying a widow because not all fingers are alike (euphemism meaning that she will not be satisfied sexually and will come to denigrate her new husband – Rashi)]- nevertheless it is not mentioned by poskim. In Shulchan Aruch (E.H. 119:5) it only mentions that in the case of a woman who was divorced because of licentiousness – it is not proper for a man of good reputation to marry her. And also (Shulchan Aruch E.H. 119:2) a man should strive to marry an appropriate woman. The issue of marry a divorcee is not mentioned at all despite being stated explicitly in this gemora. Obviously then the gemora is not saying halacha but simply good advice. This understanding is stated by Teshuvos Maimonious (Hilchos Avel 20) – that the gemora in Pesachim is only good advice and there is no prohibition to marry a divorcee. In fact he notes that there is no place where you will find a prohibition to marry a divorcee and such is the widespread practice of the Jewish people.  The only prohibition is where in fact  he is thinking about someone else as stated in Nedarim (20b), A person should not drink from a cup and yet have his thoughts focused on another cup – even if both women are his wives. This is also the psak of Rambam (Hilchos Issurei Bi'ah 21:12), Our Sages have prohibited a person to have sexual relations with one woman while he is thinking of another woman. Nevertheless there is no prohibition to marry a divorcee while her former husband is alive because of concerns she might be thinking about him. It is simply good advice to avoid unpleasant situations – but it is not a halacha.

Nedarim(20a):Imma Shalom [wife of Rabbi Eliezer ben Hyrcanos] was asked, "Why are your children extremely beautiful? She replied to them, "I don't speak with my husband [i.e, have sexual relations- Rashi]  not at the beginning of the night or the end of the night but only as midnight. When he speaks he uncovers a tefach and covers a tefach and he acts as if he is being forced by a demon [either very forcefully like one possessed or like one afraid of a demon - Rashi]. I asked him what is the reason for this [waiting until midnight] and he replied, "In order that I not think about another woman which if I did would cause the resulting children to be like mamzerim."

Kallah(1:10): They asked Imma Shalom the wife of Rabbi Eliezar and the sister of Rabban Gamliel – "Why are your children so beautiful? And when having sexual relations – how does your husband conduct himself?" She replied to them, "He does not talk with me [i.e, have sexual relations- Rashi] at the time of the first watch or at the time of the last watch but only during the middle watch. He uncovers a tefach and covers a tefach and he acts as if he was being forced by a demon [either very forcefully like one possessed or like one afraid of a demon - Rashi]. I asked him, "What is the reason for this?'  and he replied that it was in order that he would not be thinking of another woman while having sex with her which would cause the resulting children to be like mamerim." From here they say that there are 10 children that are like mamzerim but are not actual mamzerim. The child of a Jewish slave, of a non Jewish slave, of hatred, of niddah, of nidoi, of mistakenly thinking she was another woman, of strife, of intoxication , of a wife you decided to divorce, of unknown woman and some say of sleeping woman....

Nedarim(20b): Do not go after your heart  Rabbi Yehuda HaNassi said we learn from this verse that one should not drink from this cup and be thinking about another cup. Ravina said that prohibition applies even if both of them are his wives.

Ramban(Toras HaAdam – Shaar HaAvel – Mourning): Our Sages taught (Mo'ed Kton 22a) There is a prohibition for a mourner to marry for 30 days. If his wife died it is prohibited forhim to marry another until 3 holidays have passed. Rabbi Yehuda says he can marry on the 3^rd holiday. The explanation of this distinction is that the Sages were more strict in the time for him to take another wife in order that the first wife be forgotten and he won't be thinking about the first wife while having sexual relations with the second. This prohibition is in Nedarim (20b),Do not follow after your heart – from here Rabbi Nosson learned that one should not drink from this cup and think about another woman. Ravina says this prohibition applies even if both are his wife. Furthermore it is prohibited to prevent having children that are from one of 9 prohibited relations – either a child of mixture (arbuvia) or a hated child. However if he has no children then it is permitted for him to get married immediately to avoid nullifying the command to have children. If he has small children then it is also permitted to get married immediately in order that they be taken care of.

Sefer haManhig(Perishus, Taharah, and Kedusha) Rabbi Nosson said, The verse "Not going after your heart and your eyes" is prohibiting drinking from one cup while thinking about another woman – even if both are his wife. But this seems to contradict [what Yaakov did] as it says, "It was morning and behold it was Leah". That means that he was thinking about Rachel while he was having sexual relations with Leah. But Leah didn't get pregnant that night [and thus she didn't have a child that was one of the 9 prohibited relations]...<

Rambam(Hilchos Issurei Bi'ah 21:12): Our Sages prohibited having sexual relations with one woman while he is thinking about another woman.

Shulchan Aruch(O.C. 240:2): A person should not drink from one cup while he is thinking about another cup – even if he is married to both. [while having sexual relations with one woman he should not be thinking about another Magen Avraham O.C. 240:6).