Jose, I think that falls into the "I am not surprised he is having sex with his employees" category.
I haven't read "everything" that's out there, but...
He's certainly not the first "boss" to have sexual relationships with his employees, and he most certainly won't be the last.
Even though he had been seeing the mother of his child for two decades, they did not marry until this past March. So, unless, some of the "terrible things" happened during the past couple of months, well...
And I do admire Mr. Letterman for wanting to protect not only his family, but also staffers with whom he had sexual relationships. -Now, if some of those staffers decide to make their identities known, well...