"As long as neither party is being exploited".
The thing is this is endemic within the sex industry. Take Amsterdam for example, they have just opened some government run brothels, as there are concerns that about the trafficking within the 'normal' windows. That the current guidelines for these windows is not strict enough and that abuse of women within the system is far too common.
So now there is a street of government run brothels, only they've had to close them for all the day time shifts as they can't get enough women in who pass the stricter criteria. And they are only partially occupied during the evening by women. It's being touted as a failure.
In essence, when the criteria is non-exploitation, the business models can't survive.
So for me the question of who is buying the sex is irrelevant.