Before they were married, Ryan's fiancee caught him checking out some other girl's cute ass. To his surprise, she was okay with it. What's the harm in a little fantasizing?
The lovely Nina even revealed that she fantasizes sometimes, too. She checks out the hot guys, sometimes. It's not like cheating. Everyone does it.
Only when Nina tells Ryan that she fantasizes about other men, it turns him on. And now he fantasizes about her getting to live out her fantasies and actually sleep with other men