WASHINGTON (AP) - A Nevada man whose wife had an affair with Sen. John Ensign said he discovered the relationship after intercepting a text message around Christmas in 2007.

"How wonderful it is. ... Scared, but excited," it read.

Doug Hampton recounted the text message during an interview taped for broadcast Monday night on ABC's "Nightline." The interview covered a lot of ground already made public since Ensign, R-Nev., admitted to the extramarital affair in June, but provided new details about how the affair was discovered as well as the senator's reaction when Hampton confronted him.

The acknowledgment of the affair has led to a huge fall from grace for a man that many viewed as a rising star within the GOP. He's now fighting to complete a second term in office that continues through 2012.

The Hamptons and Ensigns had been close family friends for years. Hampton told "Nightline" he confronted Ensign when both families were present during a Christmas Eve gathering.

"John cries like a kid. Puts his head in his hands, cries like a little boy," Hampton said, adding that he heard remorse and panic in his old friend's voice but now believes it was disingenuous.

Hampton continued to work for Ensign as his co-chief of staff. He said that the two went on a trip to Iraq in February 2008. He said he was having troubles with his telephone and asked to borrow Ensign's to call his wife. He said Ensign scrolled to a listing for Aunt Judy instead of Cindy Hampton. "And then I realize, Wow, wow, something is seriously wrong," he said, that the affair was still going on.

Hampton makes clear through the interview he isn't going away quietly and believes Ensign abused his power in pursuing the affair. Ensign's legal team has said it's confident that all laws and ethics rules were followed in the case, which includes Ensign helping Hampton gain employment with a lobbying firm as well as Ensign's parents providing the Hamptons with a payment of nearly $100,000 that they described as a gift.

"I truly wish that I could publicly respond to each one of Doug Hampton's allegations," Ensign said. "They are full of half truths and untruths. I will cooperate with any investigation because I have not violated any law or Senate ethics rule. If Doug Hampton violated federal law and rules, I did not advise him to do so, I did not suggest that he do so, and I did not cooperate with his doing so."