On Saturday, The Real Housewives of New York City star posted an old photo of Shields playing with their two dogs. Alongside, Frankel looked back at the loss with some touching words.
"One year ago today, I woke up to a beautiful sunny day with @biggysmallz by the pool, and my world crumbled and turned upside down in an instant," the 48-year-old reality TV star wrote, referencing her dogs' Instagram account. "A man Dennis, who I loved and respected, who was in my life for 30 years unexpectedly passed away."
Then, Frankel shared a sweet anecdote about how she and Shields chose their dogs' names, showcasing his thoughtfulness.
"Dennis insisted we adopt biggy AND smallz for my daughter Peanut," she wrote, in a nod to her 9-year-old daughter Bryn's nickname. "He simply couldn't imagine separating them. We racked our brains staying up late coming up with the perfect name for two dogs from the same litter with very different body types. Thing 1 & Thing 2 was an option but Peanut found it degrading. Lenny & Squiggy was a good one but I knew it would only appeal to the over 40 set."
"Then at 5am, Dennis was waiting for me to wake up and in his stronger than Tequila New Yawk accent said 'BIGGY AND SMALLZ' and two stars were born," she continued. "He loved these dogs and the feelings were mutual. They were particularly fond of his salty bald head."
Frankel went on to discuss her late ex's special bond with the dogs, then concluded by discussing how she is still processing the loss.
"At times, it seemed like he and they spoke the same language and they were the only ones who understood him," she shared. "He was a loving, sweet, gentle, brilliant, complicated, hilarious, creative and supportive man. He is missed terribly by so many but lives on in his friends and family and furry loved ones."
The reality star ended by writing: "I am a different person and in a different emotional place than I was a year ago, and the wounds have begun to heal but the scar will remain on my heart forever. RIP, August 10. #Unforgettable."
A year ago, Shields was found dead of a suspected accidental overdose at his home in Trump Tower in New York. However, the cause of death was ruled "undetermined" by the New York City Medical Examiner's office.
In the season 11 premiere of RHONY in March, Frankel recalled how she discovered that Shields had died.
"Dennis passed away three weeks ago in his apartment," Frankel recounted. "Tyler, his daughter, called me, hysterically crying and she said, 'My dad died this morning.' And I started screaming into the phone."
In the episode, Frankel also shared with her daughter her final text message to her late boyfriend: "I love you, Dennis, and I always will. You're the most loving, beautiful man in the whole world and I'm sorry you were in so much pain. Now, you can really sleep."
Read more on Shields and Frankel below.