I usually don't really pay any attention to author's biographies. I'm more interested in the literature, and a part of me doesn't really want to know about the author's personal life. There are many actors and musicians that I am not very fond of, because we see their real life on the TV and in the magazines and a lot of them aren't very admirable people. So I try to just focus on their work, and not the people they really are. I guess that has carried over into authors, even though most authors are much more stable and normal people than actors and musicians. :)
There hasn't ever been an author that I have stopped reading just because of their own life story. I can only think of a couple of authors whose stories I know. One of them is Nicholas Sparks. I have a love/hate relationship with him, because I love his style of writing and the stories he writes but I sometimes have a hard time with the deaths that always take place in his books. I remember complaining about this to my mom one day, and then she told me the story of Sparks' own life - which has involved sadness and tragedy and death. I haven't read his book Three Weeks with My Brother, but my mom told me about it. It helped me understand why he writes the kind of stories he does, and to have more of an appreciation for them.
The other author whose story I know is Jane Austen. I didn't go looking for her life story either, but I watched the movie Becoming Jane, and I loved it! It made me want to go and read about Jane's real life. Reading about her and her family, her short-lived relationship to Tom LeFroy, and the fact that she remained single - they all add another layer onto her books for me, and I appreciate that.