In welfare-houses or other institutions for the reception and maintenance of poor persons, females shall be kept separate from males at all times in their living rooms, bedrooms, toilets, halls, stairways and outbuildings, except that the provisions of this section shall not apply to persons who are lawfully married and living together as man and wife and who are or shall become inmates of a welfare-house or other institution. The accommodations necessary to carry out the intentions of this section shall be provided.