Are married couples forbidden from sitting together on one sofa?

Shalom and blessings,

I will begin by noting that according to the custom of Ashkenazim, it is forbidden for a husband to sit on a bench that sways, and is not fixed or attached to the wall, when his wife is a niddah sitting on it, because since the bench sways, the husband feels his wife sitting. This is the ruling of the Rema, Yoreh Deah, section 195, subsection 5. However, the custom of Sephardim and most Eastern communities is to be lenient in this matter (Taharat Habayit, part 2, section 12, subsection 2).

As for a sofa: if it is heavy and rests firmly in place, then even according to the custom of Ashkenazim it is permitted to sit on it at the same time, and although the cushions are soft and a person can feel, through the softness of the cushions, that another person is sitting there, it is permitted to sit on it (Mishmeret HaTaharah, part 2, section 8, subsection 71, in the name of Rav Elyashiv, of blessed memory); however, one should place an object between them (ibid.). According to the above custom of Sephardim, it is plainly permitted even without an object separating them.

And if the sofa is divided into several cushions, so that one does not feel the other person sitting, then even according to the custom of Ashkenazim it is permitted to sit without an object separating them. But of course, they must be careful not to touch one another.

With blessings,

Hillel Meirs