Beautiful Mistake

The book was interesting till I came to the part where the hero (who is a professor) casually admits to having slept with HIS students.

“I have no idea why, but I decided to embellish the last rumor to satisfy my own curiosity. “You're married and you almost got fired for sleeping with your students.”
The look on his face told me I'd hit a sore spot. Caine's jaw clenched, and his full lips thinned as they drew into a line. “Not married and stopped sleeping with my students after the first year.”
I crinkled my nose. “So you used to sleep with your students?”
“I was young and stupid. The first year I taught, I spent almost all of my time on campus. It was the only place I met people.”
“Ever hear of match.com?”
“Of course, wiseass. But people are rarely what they seem online.”
I scoffed. “Tell me about it.”
Caine raised an eyebrow. “Sounds like you know from experience.”
“Just last night in fact.”
“And...”
“And he only had one thing on his mind.”
“Sex?”
I nodded. “Men can be such assholes. No offense.”

I am sorry, WHAT?! Even after he confessed to sleeping with his students the conversation went on as if nothing happened. How is this okay ...