I'm not a divorce lawyer but this definitely involves fucking over a spouse. I know someone who's father in law died and his wife had some half-siblings who she really didn't get along with. The wife wanted to scatter the ashes where her father wanted, but the half-siblings wanted to scatter them next to their mothers, who the wife's dad left her mum for.

It went on for a while and it was suggested they split them in half, well the couple went to collect the ashes and explained the situation to the woman at the crematorium. Apparently they had recently cremated a 'Jane Doe' and she made the strange decision to hand over the fathers ashes along with the unidentified woman's.

So the wife tells the half-siblings she's had enough and they can have the ashes (obviously giving them the random woman's ashes) and then finds out a while later that her half brother had a tattoo with some of the ashes sprinkled into the ink lol

Some time passes and the couple have now split up and he found out his wife had been cheating on him, that's a pretty big secret to hold over her and she is going to get royally fucked over when he decides what to do with that info