Former President Bill Clinton says his worst day in the White House was the day he told his wife Hillary about his affair with intern Monica Lewinsky. Mr. Clinton made the comments in an interview with the CBS television program 60 Minutes to promote his autobiography, which is being published this week.

In a wide ranging interview about his life and his presidency, Bill Clinton explained why he engaged in a sexual affair with White House intern Monica Lewinsky in 1996 and 1997.

"I think I did something for the worst possible reason, just because I could," he said. "I think that is just about the most morally indefensible reason that anybody could have for doing anything, when you do something just because you could."

At first, Mr. Clinton lied about the affair, not only to the public but to his wife as well. That eventually led to Mr. Clinton being impeached by the House of Representatives. He was later acquitted in a trial in the Senate.

But Mr. Clinton said the worst moment of his presidency came in August of 1998 when he had to tell his wife, Hillary, the truth about his affair. "I had a sleepless night and woke her up and sat down on the side of the bed and just told her," he said. " And it was awful but I had to do it."

In his autobiography, entitled My Life, Mr. Clinton wrote that his wife looked at him as though she had been punched "in the gut."

Bill Clinton told CBS that despite the personal failings that led to him becoming only the second American president impeached, he will always see it as a badge of honor.

"I will always regret the personal mistake I made. But I will always be proud that when they moved on impeachment, I did not quit, I never thought of resigning and I stood up to it and beat it back," he said. "To me, the whole battle was a badge of honor. I do not see it as a great stain because it was illegitimate."

As for his own accomplishments in office, the former president said he is most proud of his economic policies that produced 22 million new jobs during his eight years in office.

As for his disappointments, he mentioned his failed effort to expand health care benefits and shore up the Social Security retirement system.

But he said there were disappointments in foreign policy as well.

"In international affairs, I regret that I did not succeed in getting Osama bin Laden and equally I am sorry that I was not able enough to convince the Israelis and the Palestinians to make peace."

On the current situation in Iraq, Mr. Clinton said he is generally supportive of Bush administration's approach at the moment.

"In terms of the launching of the war, I believe we made an error in not allowing the United Nations to complete the inspections process," said Mr. Clinton. "Now, having said that, we are where we are and I think the most important thing now is for all of us to support a stable, peaceful and pluralistic Iraq and it looks to me like the [Bush] administration is moving in that direction."

The demand for Bill Clinton's book is high and could intensify during his upcoming national book tour. But the book is already getting its share of criticism including a review by The New York Times that described it as "sloppy, self-indulgent and?dull."