GEMARA

(Mishnah): If a woman told her husband during relations that she felt a flow of blood that makes her a Nidah, if he withdraws the Ever (during erection), he is Chayav Kares, because withdrawing it is pleasurable, just like inserting it.

18b (R. Shimon ben Yosi): The Lav forbidding relations with a Nidah is "v'El Ishah b'Nidas Tum'asah Lo Sikrav."

(Rav Papa): If a woman told her husband during relations that she became Nidah, "Lo Sikrav" is a Lav forbidding him to withdraw immediately. "Lo Sikrav" can also mean 'do not separate' - "Kerav Elecha Al Tigash Bi."

Sanhedrin 37a - A Min: You permit a Nidah to be secluded with her husband. Is it possible that a fire will not singe chips?

Rav Kahana: The Torah testified about us - "Sugah ba'Shoshanim", we do not breach even a wall of roses.

Kesuvos 4a (Beraisa): If the Kalah becomes Nidah, he sleeps among men, and she sleeps among women.

4b: This is when she became Nidah before they had Bi'ah.

Shabbos 11a (Mishnah): Similarly, a Zav may not eat with a Zavah.

13a: This is lest they come to have relations.

Question: May a Nidah sleep (in the same bed) with her husband, when each is in his or her own garment?

Answer (Rav Yosef -- Mishnah - Beis Hillel): Fowl and cheese may not be on the same table, or eaten together. (We similarly decree about a Nidah.)

Support #1 (Seifa - R. Shimon ben Gamliel): Two lodgers may eat at the same table, one meat and the other cheese, and we are not concerned.

R. Chanan bar Ami taught that this refers to strangers, but if they know each other, it is forbidden. A husband and wife know each other!

Rejection: Lodgers who know each other are forbidden, for there is no Shinuy. Here, there is a Shinuy! (Normally, they sleep unclothed).

Support #2 (Mishnah): A Zav may not eat (with a Zavah...)

Rejection: There also, there are two people, but there is no Shinuy!

Rav Yosef argues with R. Pedas, who expounds "Lo Sikrevu Legalos Ervah" - the Torah forbids only Kirvah (closeness) of Giluy (Bi'ah with) Ervah.

(Tana d'vei Eliyahu): Once, a learned Talmid died very young. His widow was complaining why "it (Torah) is the length of your days" was not fulfilled. Eliyahu asked about his conduct with her during the seven clean days.

The widow: He would eat and drink with me, and sleep (in the same bed) without clothes (on either of us), but he never even considered relations!

Eliyahu: Blessed is Hash-m who killed him, and did not show partiality due to his Torah! It says "v'El Ishah b'Nidas Tum'asah Lo Sikrav"!

RISHONIM

Rambam (Hilchos Isurei Bi'ah 11:18): One may not cling to his wife during the seven clean days... he may not eat with her from one bowl.

Ra'avad: Our custom is even on one table. Rav Acha agrees.

Beis Yosef (YD 195 DH u'Mah she'Chosav v'Lo Yochal): The Rashba explains that even on one table is forbidden. It suffices to spread a cloth on the table for a Heker. Some are lenient like the Rambam. The Ran (5b DH v'Chosav) says that the Gemara supports the Rashba. R. Yerucham says that some make a Heker between them, or they eat on two cloths or they fold over the cloth. Some permit that she changes and does not eat in her place. The custom is to require a Shinuy.

Hagahos Maimoniyos (30): One may not eat with at the table unless there is a Shinuy, e.g. bread or a bottle between his bowl and hers, for Shabbos 13a compares this to two friends eating meat and milk at one table, which is forbidden without a Shinuy.

Rosh (Shabbos 1:32): Nowadays the custom is to eat with Ishto Nidah on one table. Before, everyone used to eat alone on a small table. When his wife was with him at the small table, this showed affection. Nowadays the household eats at one table, so it does not show affection. Some make a Heker between them, like two people eating at one table, one milk and one meat.

Hagahos Ashri: If when she is Tehorah they eat from one bowl, and now they eat from separate bowls, this is a Shinuy; it is permitted.

POSKIM

Shulchan Aruch (YD 195:1): One must separate from Ishto Nidah until she counts seven clean days and immerses. He may not jest with her or be lightheaded (Rema - even verbally), lest this lead to Aveirah.

Beis Yosef (DH u'Mah she'Chosav v'Lo Yishtamesh): The Rashba learns from Avos d'R. Noson (2:1). It expounds "v'El Ishah b'Nidas Tum'asah Lo Sikrav" to forbid hugging, kissing and speaking idle words.

Shulchan Aruch (ibid): He may be secluded with her. Since he once had Bi'ah with her, his Yetzer does not overpower him.

Shulchan Aruch (3): One may not eat with her at the table unless there is a Shinuy, i.e. something separates between his bowl and hers, bread or a bottle, or each eats on his own cloth.

Taz (1): The bread or bottle does not permit if they eat or drink from it.

Shach (6): It suffices if they uncover part of the table, and her bowl is on the table (without a cloth).

Gra (8 and Likut in 88:2): The first opinion in Tosfos (Chulin 107b DH k'Ein) holds that a Shinuy suffices for meat and milk. The same applies here. A Shinuy permits everything, except sleeping together. Many rule like the second opinion, that a Shinuy does not permit eating together (meat and milk, or with Ishto Nidah). However, scrutiny shows that the first opinion is correct. We conclude that Rav Yosef argues with R. Pedas, who says that the Torah forbids only Kirvah of GIluy Ervah. We must say that Shinuy permits eating; and they argue only about whether it permits sleeping.

Gra (Likutim here (8) and 88:2): We hold like the latter opinion in Tosfos, that a Shinuy does not permit eating together. The Rosh, Mordechai, Avi ha'Ezri, and She'altos forbid. It was a mere Dichuy in Shabbos to say that Shinuy permits. The conclusion forbids sleeping in one bed, or eating at the same table.

Rema: Some require a separation between their bowls only if when she is Tehorah, they eat from separate bowls.

Shach (7): The Bach says that this leniency is only when others eat at the table with them. If not, even if no one else is there, we forbid even if they normally eat from one bowl. The Bach is not necessarily correct.

Rema: If when she is Tehorah, they eat from one bowl, it suffices for her to eat from a separate bowl. This Heker suffices. This is the custom. Some say that he may not eat from her leftovers, just like he may not drink her leftovers.

Shach (8): Darchei Moshe (4) found this in a treatise. Really, it is from Hagahos Maimoniyos and the Mordechai. They say oppositely, that we learn the Isur to drink her leftovers, from the Isur to eat leftovers!

Gra (10): The Gemara said that the Talmid ate and drink with his wife during her seven clean days. Also this justified his death. He sinned by drinking her leftovers, and similarly regarding eating. We forbid a Zav to eat with a Zavah, i.e. after her, but not vice-versa.

Note: In Shabbos, Amora'im explained why the Talmid was lenient to sleep with her, but not why he ate and drank with her.

Taz (2): Some cut the food into small pieces, and they take one by one until they finish eating. This does not help, unless each first puts the food on his own plate before eating it.

Taz (3): The Bach says that since we equate eating to drinking, she may not bring food to him. This is difficult, for Ishto Nidah may do all labors, except for mixing his drink... (Kesuvos 61a). We did not list bringing food among them! It seems that Chachamim estimated that this does not cause closeness. It is merely a labor of toil, unlike mixing his drink.

Pischei Teshuvah (YD 195:10): Perhaps one may not hear Ishto Nidah sing. Shabbos 13a connotes that whatever is Asur with an Eshes Ish is Asur with Ishto Nidah, except for seclusion. This requires investigation.

Taz (4): If someone else ate from her food in between it is permitted, just like if someone drank from her cup in between. Likewise, all leniencies of drinking her leftovers apply here.

Shulchan Aruch (OC 217:4): One may not bless on fragrances of Ervah, e.g. if it hangs on her neck or is in her hand, for one may not smell it, lest he come to kiss or touch her.

Taz (3): The Shulchan Aruch discusses the usual case. It is forbidden even if she removed it, for the fragrance is made for Ervah (i.e. to arouse desire). Further, it will cause him to have thoughts if he knows her.

Birkei Yosef (3): It is proper not to smell perfumes of Ishto Nidah. Even though Chachamim did not decree about seclusion, and the Torah testified "Sugah ba'Shoshanim", one must distance himself. The verse hints that a Seyag (fence) is needed even for Shoshanim (roses, i.e. Yisrael).

Pischei Teshuvah (YD 195:1): Likewise, one may not smell perfumes of Ishto Nidah even if they are on the table.