I suspect so many of us see examples of corporate crime or even of corporate greed (legally) causing an incredible amount of damage that an affair feels trivial in comparison. That is especially true when the private family life of a CEO is private. The damage of the affair could be anything from devastating to the family to they were all but legally separated.
Two wrongs don't make a right.
You should be concerned about corporate crime.
That doesn't change that there is a conflict of interest here and any company should fire someone who has a conflict of interest that they are not carefully managing to ensure they don't become real.
I can hardly imagine anything more stupid than judging the aptitude of the CEO of a 5T$ business based on his private love life.