Photo: ABC News

Despite their efforts to keep the affair a secret, rumors about John's relationship with a woman who worked on his campaign began swirling in the media. Publicly, John dismissed the reports and denied having an extramarital affair.

On January 30, 2008, he dropped out of the presidential race.

Months later, the truth finally came out. As millions watched, John admitted during a Nightline interview to cheating on Elizabeth. "Let me say this, and I want to say it absolutely clearly. I was wrong, and I am responsible," John said.