Joking about cheating on a spouse is unacceptable. Sure, you may fancy yourself a comedian, but putting someone through the emotional turmoil of thinking they were just betrayed is awful. And this dude is exactly that — awful. So, what exactly happened? Well, this couple was enjoying a nice date on their boat, out in the morning sun, when he suddenly became very serious and told her that he had something to tell her. Uh oh, that's never good. Although she was scared, she prompted him to go on.…