Shawn Weber, Attorney and Mediator
The short answer is “none” because California is a “no-fault” state.
This means that evidence of adultery, as a general rule, is not permissible in court as it is not relevant. However, perhaps that answer is a bit simplistic. Evidence of an affair can come in if it is used to prove a fact that is relevant.
For example, I had a case several years ago where the husband had used community property funds to purchase expensive jewelry for his mistress. I represented the wife and brought the evidence of the jewelry purchase into evidence – not to show that there was adultery, but that the Husband had violated his fiduciary duties by secretly purchasing the very expensive jewelry with community property funds. In another case, I was able to bring evidence of of an affair in where the opposing party had invited the parties’ five-year-old child to sleep between her and her boyfriend. Again, I did not bring the evidence in to show that there was cheating. Rather, the evidence came in to show that the minor child was inappropriately being exposed to her mother’s sexual behavior.
So, the rule in a nutshell is that evidence of adultery generally does not come into evidence because the fact that an it occurred is not relevant in a no-fault state. However, where the evidence that shows that adultery occurred also shows that something occurred that is relevant, the evidence can come in, but only to show the truthfulness of the relevant fact and not the alleged adultery. (That the judge learns of the adultery as a consequence is a nice little bonus.) Importantly, the mere fact that adultery occurred cannot be considered by the court in dividing property, dividing debt, awarding support, awarding attorneys’ fees or determining child custody in a divorce.