Adam Benson was a businessman from Bedford, Iowa who killed his wife while under the influence of a siren.
History
Adam came home from work to find his wife making dinner. She immediately commented about his boss keeping him at work late so often. He snapped at her and they apologized to each other. After he snapped at her again for committing them to attend a friend's 40th birthday party, she accused him of gunning for a fight. He then picked up the meat tenderizer she'd been using and bludgeoned her to death.
When the Winchesters visited him in jail posing as attorneys, he told them he didn't want a lawyer; he was going to plead guilty. They angled to find hints of possession, but Adam reported that he was crystal clear and in control when he killed his wife for making plans without asking him. He didn't know why he killed her, though, because he loved her and they were happy. When Dean produced a credit card bill that detailed $9K worth of charges from a strip club, he finally confessed that a stripper named "Jasmine" had first approached him at a bachelor party and became everything he ever wanted. She'd convinced him that they could be together forever if only his wife was out of the picture. He was supposed to meet her after he killed Vicky, but she never showed up. When Sam asked him why he didn't tell the police about Jasmine, he replied that there was no reason to because she didn't kill Vicky, he did. He told them that if the judge didn't give him the death penalty, he'd do it himself.