4 ideas
Leo and Sophia Tolstoy each read the other's diaries throughout a marriage begun in 1862, and each wrote knowing the spouse would read it. In 1910, his last year, Tolstoy began a secret diary 'for myself alone' and hid it in his boot.
A diary written in the knowledge that a specific person will read it stops being a private record and becomes an address to that reader: pleading, accusation, self-justification. The text still has the form of confession but works as persuasion, so it has to be read as one side of a conversation, not as raw inner life.
Sophia copied War and Peace by hand repeatedly, bore thirteen children, managed the estate and handled publishing, and her diary records the cost of this work that the published canon credits to one man. The mechanism is that output gets attributed to the named producer while the support work that made it possible leaves no trace except in the supporter's own private record.
Early in the marriage, reading each other's diaries was a pledge of total transparency; Tolstoy gave Sophia his premarital diaries, with their sexual history, before the wedding. The same openness later became a tool of control, and every entry became evidence and ammunition. A norm of full disclosure leaves no private space for either person to think, so honesty turns into performance and the partners grow further apart.