After her mom's death, Natalie Wood's daughter Natasha Gregson Wagner remembers how her stepfather Robert Wagner confirmed the news she had drowned. "It was just the unthinkable," says Natasha. "I just remember it was the worst thing ever. My whole world just went to black and white and I couldn’t hear anything…"
In the months and years that followed, Natasha, 45, the daughter of Wood and her second husband Richard Gregson, grew exceptionally close to Wagner, who raised Natasha, Katie Wagner (his daughter with his second wife, Marion Marshall) and Courtney (his daughter with Wood) together.
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"I grew up always thinking I had two dads," she says. "I'm certain because my mom died, my relationship with my stepdad is way deeper than it would have been had she lived, because he had to be my mom and dad."
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In turn, she saw his sadness up close. "Before my mom died, my dad was a happy go lucky person and kind of the life of the party," she says. "After she died, when I would look at him from a distance, from my bedroom window walking into the house, there was a heaviness and a sadness to him that hadn't been there before."
"He's better now," says Natasha, who has created a new fragrance in honor of her mom. "We've been in a lot of family therapy, my family and I, to process everything and by the grace of God, we all moved forward."
Wagner, 86, feels the same way. "My bond with her is very, very intense," he tells PEOPLE. "We've hung on to each other throughout the years and she means the world and all to me."