As the investigation into the extortion case continues, Letterman is likely to remain in the spotlight.
It's unknown how many staffers Letterman was involved with, but reports say the liaisons took place before he was married and before the birth of his son, Harry Joseph Letterman, in 2003.
"I feel like I need to protect these people. I need to certainly protect my family," Letterman said when making the awkward announcement of his affair.
Earlier this year, Letterman married his longtime girlfriend, Regina Lasko, a former member of his staff, who he began dating in the 1980s. They wed March 19, 2009, at the Teton County Courthouse in Choteau, Mont.
After announcing his wedding during his show March 23, 2009, he said, "I had avoided getting married pretty good for, like, 23 years and I ... secretly felt that men who were married admired me, like I was the last of the real gunslingers."
Letterman remained unmarried for a long time after his first marriage to college sweetheart Michelle Cook ended in divorce in 1977. He dated another staffer Merrill Markoe, a comedian and author who was his longtime writer when he was on NBC, in the 1980s.
This is not the first extortion plot alleged to have targeted Letterman. In 2005, Kelly Frank, who worked as a handyman on Letterman's Rocky Mountain ranch in Montana, was arrested for allegedly plotting to kidnap Letterman's then-16-month-old son, Harry. Kelly allegedly wanted $5 million for the return of Harry and his au pair. Frank first pleaded not guilty but later copped a deal of felony theft and other lesser charges and got 10 years in jail in 2005.
ABC News' Michael James, Lindsey Goldwert, Kate McCarthy and Richard Esposito contributed to this report.