The issue is this.
It doesn't matter that he is fucking someone, or the fact that he is cheating on his wife.
The problem is he is fucking someone who works for him and the university...that becomes a slippery slope. (pun intended)
She can say that he offered her a better position for sexual favors, and SHE CAN SUE THE SHIT out of the University for sexual harassment. Everything always comes down to money. That is the ONLY reason he is suspended right now and could be terminated.
If you are a boss you don't fuck the help.