I don't get this "abuse of power" angle at all. Having a relationship with a subordinate is not an abuse of power. Insisting that your job rests on a relationship is an abuse of power, but without evidence that happened (and it seems like it didnt), there's no abuse. This idea that a power differential invalidates a relationship is nonsense.

The fact is, people spend half or more of their waking hours at work. You spend more time with your colleagues than you do your own family in many cases. Relationship are going to happen. We need to learn how to deal with it rather than try to codify rules against it.