Mr and Mrs Smith (2005)

John and Jane Smith are a married couple, both living unexciting lives and attending marriage therapy, as their passion has cooled since they got married. But what they don't know about each other is that they are both professional assassins working for two rival agencies. John's latest assignment is to eliminate Benjaiman "Tank" Danz, but it all becomes complicated when Jane is also assigned to eliminate the same target. Learning that they are both assassins and failing to eliminate Danz, John and Jane's separate employers decide that they try to take each other out (John kill Jane, Jane kill John). Engaged in a deadly game, John and Jane try to take each other out and learns more about each other as they try to finish the job and eliminate Danz.