He is obviously a twat, his hands were cupping her breaths, who does that, in public?
There were other work people there, again, indicator of being a knob. I m going to guess he gets a kick out of pushing things too far, it's exciting fir him to display his affair in front of the other staff members, exciting that the other HR staffer was in on his rule breaking, exciting to cup his affair partner's breasts in public.
When caught, he immediately went into self protection mode. He is not chivilrous or considerate, he likes cheap thrills and getting away with it.
Now that the affair is public knowledge and has damaged him, he ll be looking for someone else to blame. When that blows up in his face, it'll be the mental health, get out of jail card.