I know a man who didn't have to pay alimony because he proved his wife cheated on him. She got the furniture in the divorce, and that's about it.
He hired a PI to follow her moving truck to its destination - and she wasted no time. She went to a nearby motel where she picked up her new man, and the PI got photos of them at every stop between San Diego and Phoenix AZ kissing and grabbing each others butts. From what I'm told, the lawyers on both sides had extreme reactions.