Husband Sent Affair Partner Money…

(CA) Hi, as the title reads ..my husband had an affair for at least a year and he sent money to his affair partner through her business account. I’m not sure if he did this to not raise a red flag with me or if he was trying to hide money , but I do know that at some point during this affair she invested over $20,000 in a company my husband and I previously invested in. My question is , how is a scenario like this handled in the eyes of the court ? How do I prove my suspicions that he was trying to hide money through her to invest more into a company without me knowing? Or would that not matter in court? Edit to add state .