When The Forgotten came out in 2004, I remember commenting that it was eerily similar in plot to a movie I had watched on TV years prior.

A man awakes with some amnesia, but has a fleeting memory of a family.  People around him act as if he was never married.  The man begins to mentally unravel searching for clues of his lost family.  He eventually uncovers the plot that he is part of an experiment on memory.

And, No, its not Dark City – also an excellent movie BTW