You're probably referring to my answers about the 'invention of privacy' and that's honestly probably just my personal way of stating it. I word it that way after hearing Bill Bryson discuss the 'invention of upstairs' Other sources use slightly different phrases. I use the phrase on my research blog

For developmental histories of privacy please see the four volume History of Private Life, or Stones two volume Family Sex And Marriage in England 1500-1800. Also worth a consider is McKeon's work The Secret History of Domesticity.