I do not consider prositution as sexual misconduct, because to me, it is the same as any action that we indulge ourselves in - what differs is that we base the result on how we deem each action from our preconceived ideas.
Personally, I agree with many things said here, especially by Wisdom Being. Prostitution can be considered as a job, just that in this case, the service/business is the selling of one's body. And the buyer/client, has the right to purchase this service. It is a consensual transaction, a financial one, therefore no harm done to both parties per se. Sexual misconduct can only come from the part of the client, where he/she goes to a prostitute knowing that it will hurt their respective partners - that is sexual misconduct and they can look for other people to fulfil their desires, not only prostitutes. Anyways, how would the prostitute know that the men/women have respective partners at home waiting for them - all they care about is providing the service that has been paid for, and collecting the cash. That is it.
So, if one drinks alot, and this results in sexual misconduct from the side of the drinker, will it then result in the bar owner's/bar-tender's fault for selling the alcohol in the first place, which led to the buyer/client who bought the alcohol that played a part in him/her sleeping with someone else? Yes the service is always there, but it doesnt mean that people should "purchase" it just because it is there. We are the judge,the decider of all our actions, so prositution is not a case of sexual misconduct.