Simon: The claim he himself made that he included details in his book to prevent someone from blackmailing him?
I think this is where his lack of self-awareness always bites him. Same as with the livestream video, he doesn't seem to realize just how bad the abridged version of his events looks. If we make the safe assumption that he embellished it so the situation would not look as bad, then we come to the conclusion that having chat sex with "girls" on two occasions is the very least that he did. With all of the other things he revealed, it is not a stretch to believe that he did this regularly and often. Or that she caught him more than two times.
When he relates this part in the book, he mentions how Dijana must have felt belittled by his actions, as if she wasn't fulfilling her duties as a wife. And then, in his livestream, he confirms her fears by basically claiming that she wasn't enough to sexually satisfy him. After writing about how it traumatized her just to suspect it! That she hasn't told him to shove off and never talk to her again shows just how beaten down she is. At some point, you have to put a price on your dignity and get the toxic people out of your life.