Is it fair to punish a third party for wrecked marriage?

Debatably married men or women, who are found guilty of having extramarital affairs, often escape unscathed. It is common that the so-called "marriage wreckers" are the only ones who get punished by jilted spouses in wrecked marriages, while the "errant" husbands or wives, are left alone.

Lawyer, Gontse Simon says it is unfair to punish the third party for supposedly wrecking a marriage whereas the "cheating" spouse, who at most is an accessory to the wreckage, goes unpunished.