Mr. & Mrs. Smith (2005)

John and Jane Smith are a couple who have been married for 6 years and things appear to be normal. But it also appears that things are changing -- they are seeing a marriage counselor. And what neither of them know is that they are professional assassins. However, they are both assigned by their employers to kill the same person. When they each try to take out the target, they get in each other's way and blow the job. Now they are told to go after the person who made them miss the target. And when they learn about each other, they try to take each other out.