Let's say Alice is having an affair with subordinate Bob. One day Bob has a big screw up with something Alice assigned him, and Alice needs to reprimand him fo

Let's say Alice is having an affair with subordinate Bob. One day Bob has a big screw up with something Alice assigned him, and Alice needs to reprimand him for it (that is part of being a person's supervisor). There is no uninvolved third party to call in here -- that is Alice's job as Bob's boss. One way or another their romantic relationship will impact their professional relationship in this situation -- either Alice will be too gentle with Bob, and everyone will perceive favoritism, or Alice will be too harsh with Bob and risk damaging their personal relationship. Very few people would be able to respond appropriately here -- in either the supervisor or subordinate position (and both need to do so).