What's happening?

Alfred Hitchcock Presents: 6x10

Sybilla

Sybilla Meade reads her husbands diary and discover that he plots to kill her. In reality, it is only her husbands fantasy. She tells him that she has read his diary and has sent a copy to her lawyer with instructions to make it public if anything happens to her. Her husband is terrified and begins to protect her. She later grows ill and dies. Her husband then learns that she never sent a copy of his diary to her lawyer. She only told him that so he wouldn’t kill her.

Alfred Hitchcock Presents: Season 6 Episode 10
Dec. 06, 1960