Men far surpassed the number of women eating away from home through most of the 19th century. But, slowly more dining rooms reserved for women appeared. Usually on the second floor and often entered through a separate door, women’s dining rooms explicitly promised that patrons would not be subject to rude looks or vulgar language. Also important, separating the women from the men in a separate dining room guaranteed that women’s reputations would remain intact. As a guide to Boston said of a Temperance Eating House, “Ladies can visit this place with perfect propriety.”

See:
“From Patrons to Chefs, a History of Women in Restaurants” by Jan Whitaker on the Boston University School of Hospitality website