In America, the employer cannot control what an employee does outside of work. This means a pit boss does not have the authority to allow or not allow a dealer to date a player. I'm not saying this is a good idea for either party. Just saying the casino or pit boss have no control over a person's private life.
Also, I don't know why this would be putting a dealer in a tough spot. Have you read Nathaniel Tilton's book "The Blackjack Life". He dated a pit boss at a casino in Vegas for a while. This didn't cause him or her problems and she never knew he was a counter. In fact, they played bj together in her off time and she tried to help him play better since she thought she knew bj better than Nathaniel. Lol
Again, the casinos and/or pit boss cannot tell their employees what to do in their offtime.
If I was a pit boss, I would stay out of an employee's personal life since I wouldn't want to get sued by my employee.