Now, Wagner is speaking to People magazine
about the aftermath of his wife's death, the circumstances of which have been one of Hollywood's most enduring mysteries.
"We were all so shattered by the loss, and we were hanging on to each other," Wagner said
In his 2009 book, "Pieces of My Heart," Wagner wrote that on that outing in November 1981, he became jealous and argued with both Wood and Walken. Later, he was unable to find his wife, searched the boat along with the captain and noticed the dinghy was missing. Wagner assumed his wife had gone ashore.
The dinghy was found about a mile from the yacht and a mile from where Wood's drowned body was found.
In 2013, bruises on Wood's body led the Los Angeles County coroner's office to change the cause of death from "accidental drowning" to "drowning and other undetermined factors."
The People story, published this week, finds the 86-year-old actor opening up about his relationship with his stepdaughter, Natasha Gregson Wagner. After her mother's death, Wagner and her father, Wood's second husband, Richard Gregson, agreed to allow Wagner to continue to raise Natasha and her younger sister, Courtney (Wagner's daughter with Wood), along with his older daughter, Katie (by his second wife, Marion Marshall).
Wagner said his relationship with his stepdaughter has always been a close one.
"My bond with Natasha is very, very intense," he told People. "We've hung onto each other through the years and she means the world to me."
His wife's death hit the family hard, he said.
"You just take it moment by moment and hope that it gets better and more light comes into her life. As an adult and as a man, I could not climb into (Natasha's) head. All you can do is truly love and care for them."
Natasha and Courtney have created a fragrance named after their mother. "Natalie" is based on Wood's signature scent, Jungle Gardenia.
Wagner, who married actress Jill St. John in 1990, said his stepdaughter very much reminds him of his beloved late wife.
"Sometimes I see the way she moves or the way she walks or laughs and she just reminds me of Natalie," he said. "It's not a continuous thing, just a moment, a turn, her hair, some kind of look. It's quite extraordinary."