It's film probably from 90' but I'm not sure. It tells a story about a woman, who is living with her husband and one day she discovers, that she's been stalked by someone. She hires a detective. Her husband keeps telling her that it can be his ex-girlfriend. When the detective gets to know the truth, sb kills him. Woman goes to a hospital and finds some documents. But in the end it turns out, that during the whole film it was the husband, who was the stalker, because he suffers from mental illness. I also remember that this woman has a sister, whose husband was bullying her. Help me please, I've been looking for this film for way too long!