Michael Jackson's life was destined to end early, according to Lisa Marie Presley – but she wishes she'd tried harder to save him.

"I know it's naive to think that I could've, but I wanted to," Presley said on The Oprah Winfrey Show Thursday, where she opened up about the death of her ex-husband. "Had I just said, 'How are you?' Can I try to make a phone call? I really… regret that I didn't."

Jackson died last year at age 50 from an overdose of the powerful sedative Propofol and had a history of prescription drug abuse.

Presley believes Jackson's "God-like" existence made it difficult for people to stand up to him about his dangerous habits.

"If he didn't want you around, if you were going to make him confront something he didn't want to confront, he could make you go away – including his own family," she said. "I think that was a train heading in a certain direction that no one could have stopped. I've had to really get my head around that in order to stop the pain."

She also recalled her last "coherent" conversation with Jackson, whom she married in 1994 and divorced soon after. "I was very distanced, and he was checking to get a read, you know?" she says of the chat in 2005. "He was trying to throw a line out to see if I would bite emotionally, and I wouldn't."

When he asked her if she loved him, "I told him I was indifferent," she says. "He didn't like that word. He cried."

He also said something chilling at the end of that call: "He felt that someone was going to try to kill him to get hold of his catalogue and his estate," she says, adding that Jackson named names but that she couldn't reveal them.

Presley, 42, lives in England with her guitarist husband Michael Lockwood. She has four children.