Oh, just because he has done so many shows about infidelity or men's sex drive. He even made that movie about it (I saw it in the synagogue when he showed it at a talk he gave). It showed scenarios about how difficult it is for men to turn down flirtatious offers... I can't remember the whole deal.
It really is very difficult for a male to rebuff a propositioning, very well built, attractive, and sexually agressive young woman.
Dennis isn't kidding. I feel the same way, and I have never cheated on a romantic companion.