On Friday, the 45-year-old actress marked what would've been Bourdain's 65th birthday on social media.
Sharing a series of photographs and videos of the chef on Instagram, Argento began the caption of her post, writing, "Celebrating the most incredible man I have ever met."
"Missing you every day. Cherishing each moment we shared in our life together," she continued. "I feel your presence and your strength."
"You shine so bright within me," added Argento. "I love you my A. Happy birthday ❤️."
The host of CNN's Anthony Bourdain: Parts Unknown was previously found unresponsive in his hotel room in France in June 2018 by close friend and French chef, Eric Ripert, according to CNN. At the time, both were filming an episode of Bourdain's award-winning show.
"It is with extraordinary sadness we can confirm the death of our friend and colleague, Anthony Bourdain," the network said in a statement. "His love of great adventure, new friends, fine food and drink, and the remarkable stories of the world made him a unique storyteller. His talents never ceased to amaze us and we will miss him very much. Our thoughts and prayers are with his daughter and family at this incredibly difficult time."
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Additionally, public prosecutor Christian de Rocquigny du Fayel from Colmar, France, told PEOPLE that Bourdain died by hanging at a luxury hotel in Kaysersberg called Le Chambard, and said, "at this stage, nothing suggests the intervention of a third party."
In a statement provided to PEOPLE, the U.S. Embassy in Paris said, "We can confirm the death of Anthony Bourdain in the Haut-Rhin department of France. We extend our sincere condolences to friends and family. We stand ready to provide appropriate consular service. Out of respect for the family at this difficult time we have no further comment."
Later that year, Argento tearfully opened up for the first time about the moment she found out her boyfriend had died and discussed intimate details of their relationship while chatting with DailyMailTV.
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Facing backlash shortly after the beloved chef's death for pictures showing her getting close with a journalist friend in the days before Bourdain was found dead by suicide, Argento used the opportunity to tell her side of the story.
"People say I murdered him. They say I killed him," she said through tears in the interview. "People need to think that he killed himself for something like this? He had cheated on me too. It wasn't a problem for us. He was a man who traveled 265 days a year. When we saw each other we took really great pleasure in each other's company. But we are not children. We are grown ups."
"Anthony was 62, I was 42. We had lives, we had wives and husbands, we had children," she continued. "I cannot think of Anthony as somebody who would do an extreme gesture like this for something like that."
Argento also tearfully explained that she initially felt angry after learning Bourdain had been found dead of suicide. "I was angry [at him], yes, for abandoning me, my kids," the actress remarked. "But now it's been replaced just by this loss, this hole, that cannot be filled by anything."