Capgras delusion?
Will this be the twist I wonder?
shareFirst he would have had to actually exhibited the belief that the woman was in fact not his wife, he was more weirded out by her psychotic exterior, the constant hush tone she spoke in and her general secretiveness, of course it was all just cheap misdirection to make this film appear clever in the end, which some may find it as. As for me, not so much.
The people calling it a ripoff from Misery and Before I Go to Sleep only help to attribute further misdirection for those going into it, best to clear your head of other titles and themes before watching.