I have question about the ethics of life writing. What can I (or any other

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I have question about the ethics of life writing. What can I (or any other author for that matter) write in an autobiographical work? My life and my autobiography belong to me, so I should be able to decide what I reveal and how, but since they are so entwined with so many other lives, it seems as my autonomy is in conflict with the autonomies of the people in my life and my autobiography. For example: my girlfriend and I used to have a blog together (it’s closed now since we broke up some time ago) where we would write about very intimate things concerning our relationship and feelings and so on. We used nicknames to conceal our identity, so of all of the people who read the blog, only a handful of very close friends knew who were behind it. Although the blog is no longer available online, I have all the posts on my computer. It’s fairly obvious to me that I ought not to show any posts written by her to anyone, let alone reveal her identify to someone. But it’s not that obvious that I ought not to show posts written by me to someone. On one hand those posts have been written by me and I should be able to share them with whom I like. On the other hand many of those posts describe very intimate things about my girlfriend and sharing those would feel kind of like telling a secret that has been entrusted to you. What is the ethical way of dealing with situations like this, especially in this day and age where anyone can become a published author via the Web.