It Could Happen to You (1994)

Charlie and Muriel Lang have led simple lives for most of their existence. That's until they win $4 million on the lottery. There is a problem, however. Prior to winning the lottery, Charlie had eaten at a café and hadn't been able to tip the waitress. He had promised her, jokingly, that if he won the lottery he'd give her half of it.

This is why his wife, Muriel, decides to leave him. She doesn't want the waitress to get a cent of their money. In fact, she wants all $4 million for herself.