Privacy is, first and foremost, the separation between what is inside and what is outside, in every sense. European society and, later, the western world, started experiencing, in the 1800s, a movement that, first, reinvented the private person and, later, reinvented the reinvention of that very same person before the public. At the same time, people discovered their own body, just to find that their desires didn't fit so easily with the celebrated civilized existence.
A note-worthy behaviour was the change regarding sleepwear. A woman at the time would never appear in public in her night gown, even before her own family. That is also related to the changes in the architecture of houses; the couples are seperated, first by drapes, later by walls. The nightgown became a symbol of erotic intimacy. There was a nightgown for the young girl and a nightgown for the married woman, decorous, protector of her individuality, is no longer allowed to run around with her hair loose. Actually, the female body was never as hidden as during that time: petticoats, shorts, corsets, buttons and as many clasps as possible. By the end of the 19th century, lingerie reached an absurd level, when it came to lace.
At the same time, the fastenings allowed women to undress themselves. They hid but cultivated the possibility of showing, the female apparition became solemn because of the care in protecting themselves. The curves, the feet, the leather slippers, the fetishism for aprons which, for their domestic tone, make everyting seem allowed.
Among men, the variety is very small: suit and overcoat, in black or gray would make Baudelaire remark "this is the mourning sex". Male intimate clothig, too, had little variety when it came to shapes and adornments. The 19th century man has his energy focused on his work and, because financial activities were the most valued, those business man clothes were copied by other working men; with them, they could blend into the crowd and manipulate the symbols about the body that were established.
But contentment about the body went beyond the clothes that covered it. Aside from invasions, the excess of pudency ended up having the opposite effect, spreading desire. Desires became shameful and sins and should be cooled down. A touchy subject at the time was the search of solitary pleasure. It was recommended that young people should not spend too much time alone. There were prescriptions for how long baths should take, the danger of soft sheets, long nightgowns, of bandages and chains, in a moralist campaign that naturally caused the opposite actions: confessional boxes and doctor's offices were very sought after. Because of that, a few young people were subjected to terapeutical baths sessions with ice and even the cauterization of the urethra or the clitoris. Terrifying! In the words of historian Alain Corbin, compared with it, our celebrated submission to impulses and desires of the body seem pretty careless and even clumsy.