"They can mistake intensity for intimacy," Weiss said.
Weiss said sexual behavior is considered abnormal if a person feels the need to lie about it, or is "living a double life." But most sex addicts will keep it up until they get caught, he said, adding that of the 995 of the 1,000 people that have sought his help did so because they got in trouble.
"As long as a person thinks they can get away with it, they'll keep doing it and they won't seek help," he said.
Weiss said Strauss-Kahn's past transgressions and two failed marriages could hint at a sexual disorder. But Strauss-Kahn's third wife, French journalist Anne Sinclair, is standing by her husband despite his affair with a Hungarian economist Piroska Nagy.
"I do not believe for a single second the accusations leveled against my husband," she said in a statement translated from French.
Although the 2008 affair was consensual, Nagy reportedly felt coerced because of Strauss-Kahn's power, the New York Times reported Monday. In a letter to the IMF board that investigated the affair, Nagy wrote, "I was damned if I did and damned if I didn't," the Times reported. She also wrote that Strauss-Kahn was "a man with a problem that may make him ill-equipped to lead an institution where women work under his command."