In a blog published Tuesday by the Huffington Post, Hunter apologizes for her "wrong, selfish behavior."
"I hurt Elizabeth and her kids. I hurt her family. I hurt John's family. I hurt people that knew Elizabeth. I hurt people who didn't know Elizabeth but loved her from afar," writes Hunter.
Hunter and then-presidential candidate John Edwards began having an affair while on the campaign trail in 2006. Their relationship produced a child.
Edwards went to elaborate lengths to try to hide the affair from the public and his wife - including allowing an aide to claim he was the father of Hunter's baby.
Federal prosecutors alleged Edwards used money from wealthy campaign donors to pay for the cover-up. Jurors acquitted Edwards on one count of accepting illegal campaign contributions and deadlocked on five other felony counts. The judge declared a mistrial. Prosecutors said they wouldn't retry Edwards, and the charges against him were dropped.
After years of battling breast cancer, Elizabeth Edwards died in 2010.
Hunter went on to write a book about what happened. She also apologized for that Tuesday in the Huffington Post piece.
"...instead of apologizing when I should have, I went on to hurt more people by writing a book. I truly did not realize at that time how damaged I was and because of that, when I wrote my book I made more mistakes, ones I feel horrible about," she wrote.