So then SHE is the one who downloaded child porn. She could have guaranteed that she got custody by simply implying that he has sexually abused the children. Nasty feminist lawyers have been known to suggest it to their clients many times.
I have seen several wives of sailors attempt this. The problem is that like in this case, there is a very serious investigation, and the plot usually fails. Much safer to accuse the husband of spousal abuse, a crime where everyone assumes the man is guilty, there's rarely a charge or a trial or serious investigation. Usually the man is ordered to attend anger management or AA. In the end, it's enough to ensure the woman gets the kids. It's also enough to trigger the Lautenberg Amendment, and loss of 2A rights.