<i>&quot;But the courts don&#x27;t take notice of illegal-drug-related debts (I believe), nor do they any longer enforce the laws against alienation of affection or adultery, leaving those who are such disputes to take matters into their own hands.&quot;</i><p>IANAL, but to the best of my understanding:<p>1. An agreement regarding illegal activity is not held to be a legally binding contract. Hence, people professionally engaged in illegal activities usually rely on other means of coercion in order to enforce their agreements. Violence, threat of violence, reputation, retribution, extortion, etc.<p>2. Criminal courts don&#x27;t enforce adultery laws. Divorce courts, however, seem pretty free to take these things into at least some consideration when determining the financial resolutions of a divorce. So there are some potentially serious ramifications for adultery, even if they are indirect.