I think for the most part love has to a part of a dom/sub relationship... at least one that is going to last. How can a dom truly expect a sub to submit completely if they are not showing love and affection as well.
I do not think there are many (though who knows) but I have met subs who absolutely needed impersonal relationships, as like to a historical slavery as possible. And not as a fantasy.
So it does exist, though it does not get so much PR ;-)