Hunter told CNN's Piers Morgan on Wednesday, "I am sorry, I am absolutely sorry for my part in the relationship -- having an affair, any pain it caused anyone including Elizabeth."
Hunter is promoting a new book, "What Really Happened: John Edwards, Our Daughter and Me." She recently revealed that she and Edwards had ended their relationship.
In the book, Hunter describes intimate details about her affair with Edwards, whose campaign hired her as a videographer, and sheds light on his thoughts as federal prosecutors mounted a case against him on illegal campaign contribution charges.
Hunter said she didn't want to discuss her conversations with Edwards about the book, which she said he refused to read before publication. Hunter said their relationship produced "a great gift," their 4-year-old daughter, Quinn.