May a husband sit on his wife's bed when she is Nida, such as sitting on the edge of her bed to put on his shoes?
The Shulchan Aruch rules that a husband may neither lie nor sit on his wife's bed when she is Nida, even if she is not present in the room. According to some authorities, if the wife is away on a trip, then the husband may sit and even lie on her bed. It should be noted that this Halacha applies only to a bed; a husband may sit on a chair generally used only by his wife, such as a makeup chair, when she is Nida.
The Nida herself, however, is permitted to sit and even lie on her husband's bed.
May a husband and wife use each other's pillows or comforters when she is Nida?
If the husband and wife have particular pillows or comforters designated for the specific use of each, then they may not share those pillows or comforters. If, however, they do not have specifically designated linens, and no pillow or comforter is generally used exclusively by one and not the other, then they may use each other's pillows and comforters when the wife is Nida.
Summary: A husband may not sit or lie on his wife's bed when she is Nida unless she is out of the city. The wife may sit or lie on her husband's bed when she is Nida. During the period of Nida the husband and wife may use each other's pillows and comforters, except in the case of a pillow and comforter designated for the specific use of either the husband or the wife.