NIGHT CLASSES- Where is Your Wife?

CAUTION: May be this is the worst joke you ever read on internet. BEWARE!!

During work, John and William were chatting:
John: William, I've been taking night courses for 5 months now and I have an exam next week.
William: oh!
John: For example, do you know who is Graham Bell?
William: No
John: He's the inventor of the phone in 1876; if you take night courses you would know this.
The next day, the same discussion took place:
John: Do you know who is Alexander Dumas?
William: No
John: He's the author of "The 3 Musketeers", if you take night courses, you would know this.
The next day, once again:
John: And do you know who is Jean Jacques Rousseau?
William: No
John: He's the author of "Confessions", if you take night courses, you would know this.
This time, William got irritated and said: "And you, do you know who is George Hunt?"
John: No
William: He's the guy enjoying with your wife!! If you stop night courses, you would know this...

This was just for fun but if its related to any person then SHAME ON YOU!!!!