In a sufficiently-enlightened civilization, one, prostitution would be legal everywhere, and two, no one in the media or legal system would make an issue of anyone's (legal) sex life; including infidelity. In fact, as a punishment for those who would dare do so, they should be made to stand in a classroom, televised or videotaped, in front of a chalkboard, wearing a dunce cap, while writing at least 50 times on said chalkboard, "I will not concern myself with other people's humpity-bumpity." That would be a fittingly insulting-stupid punishment for his or her far more insulting-stupid act.
We need anti-scandalmongering laws. There's a balance that can be reached between the freedom of speech of the reporting of normal human interest stories and outright persnickety, unnecessarily judgmental, neurosis-inflaming muckraking. In the courts, for example, attorneys would not be allowed to bring up a defendant's or plaintiff's sex life unless it could be proven clearly, incontrovertibly relevant to the case. There would be no vague, self-righteous, Victorian or religion-based horseshit of, "It's relevant to the witness' character."
Face it, it's just a plain fact that a huge percentage of shallow fucking idiots wouldn't know a real priority or truly important news item if it whacked them in the face with a frying pan.