K, even if I do buy that it's not romantic love, isn't sleeping with someone who has way deep emotional feelings for you, which you clearly don't reciprocate as intensely, still pretty icky? Maybe even a bit ickier?

It's really all about the balance of power/priority in a relationship, and I'm pretty sure as a culture, we all agree that when that balance shifts too far to one side or the other the relationship is no longer supportable or healthy (and, in obviously much more extreme circumstances, illegal).