I have always wondered, do you think most guys who visit working girls find it harder to, not just date normal girls, but get intimate with them? For e.g. you are visiting wg's who are amazing at pleasing you, but then you get to the bedroom with a normal girl and your expectations are lowered so much because you find the latter just cannot press your buttons the same way as a wg can.
Back onto the topic at hand, i think if you had an open relationship then it wouldn't be a problem, but how would the majority of working girls feel about their guy fucking around with random women? I would think if she didn't like it, then she would certainly be quite the hypocrite.