Too honest man

When I talked with my MBA students, I really enjoy conversation with them because they are so mature and interesting. Their average age is thirty six.
When we had dinner altogether, I asked one MBA student if he has ever cheated on her wife or not. I was just kidding.
He said he did not want to answer.
Suddenly I realized that his reply let me know the answer.
I guess usually man says “no” when he has never cheated on his wife or tells some jokes. So his answer was simply “yes”.
I think he is not good at telling a lie and his wife knows the truth.
At the same time, I see the one reason why I am not popular among boys.
The world is not so bad place! Tomoko! Cheer up!
I know some men are like that but some are not like that.