A chilling diary from nearly 40 years ago reveals alleged daily abuse that Kathie Durst suffered during her marriage to accused killer Robert Durst.

Inside the faded and photocopied pages of her journal, she describes years of turbulence, including being slapped and punched.

Kathie's older sister, Virgina McKeon, agreed to read her late sister's journal aloud for the first time to News 12's Tara Rosenblum.

Kathie Durst appeared to have it all when she was 29. She was a medical student at the top of her class and married to a real estate baron with homes in Manhattan and Westchester.

Her journal reveals other things lurking under the surface, including an unplanned abortion and a suspected extramarital affair.

"He punched me and I fell to the ground."

"In late May '76, found out Bob was having an affair. Much trust had left our marriage by that time, but we still maintained a facade of a loving couple."

"He told me not to tell friends of family where I went to school. A few times, I slipped, and he became angry with me."

"We attended a meeting at an agency in White Plains. He told me how I should act and what I ought to say. I disagreed and he threw a gallon of water on my head...I felt humiliated and cried."

March 1976: "Abortion, unplanned pregnancy At the time I felt hopeless, helpless, sick to my stomach...I was depressed and saw a psychiatrist two to three times after the abortion."

"The abortion that must have been really hard for Kathy. That would have been devastating for her I think, I think really devastating," says her sister Virginia.

The journal is now one of the McCormack family's last physical connections to Kathie - words that shed light on alleged abuse they say they never even knew about.

"I wish I had known," says her sister, Virgina.

Kathie's sister Mary says her sibling was her best friend. She says Kathie would call her up all the time, but never mentioned the abuse.

Mary found the journal a few months after Kathie's disappearance back in 1982. It was tucked away in a bag of items Kathie brought to her home and told her to store in a safe spot.

"It was just before Christmas. She said, 'If anything happens to me, I want you to keep this if anything happens to me, give it to police.' She was so thin and just clinged to me," says Mary.

Mary says she pleaded with Kathie to leave Robert, but Kathie refused.

"She said, 'I'm going to leave him, but I can't leave now.' I said 'Oh yes, yes you can. You can stay with us. We'll pay you whatever.' She said, 'I don't have the money.' I said, 'We'll do as much as we can.' That was it," said Mary.

One month after dropping off the journal at Mary's house, Kathie disappeared.

"Why wasn't I there for her for heaven's sakes? Why didn't she tell me or just I don't know? You didn't hear about, you know, the abuse like you do now. You know, people aren't as open," says Mary.

Her sisters say there is still one more chapter that needs to be added to the story of Kathie Durst. They know that the book of Kathie’s life will not have a happy ending, but they are praying the last chapter will bring justice.

Robert Durst is currently on trial for the murder of his friend, Susan Berman.  He testified on Wednesday about his happy life before Kathie’s disappearance.

New York prosecutors are now officially looking into allegations from Bill Stevenson, the ex-husband of first lady Jill Biden. He revealed exclusively to News 12 that he had an affair with Robert Durst's wife, Kathie, just days before she vanished.

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