What if it wasn’t harassment? What if she was just a big fan, and did so willingly without any secondary motive from either of them?
There isn’t a darn thing illegal about schtupping the staff when they are willing and consenting adults. Certainly no reason to fire someone. Indicative of who he is as a person, sure, but no one should think he’s going anywhere because of it. At least not in this lifetime.
What does Dave do? Did he have groups of company people? It may be that this is the creepy story which brings him down.