Random Hearts

Police Sergeant Dutch Van Den Broek (Harrison Ford) and U.S. Representative Kay Chandler (Dame Kristin Scott Thomas) lose their spouses in a plane crash, and they soon discover that their spouses were having an affair with each other
After losing their spouses in a plane crash, an internal affairs cop and a congresswoman find each other's keys in each other's loved ones' possessions and discover that the two were having an affair.