"Thinking of you today and every day," the former "Real Housewives of New York City" cast member wrote in the caption of the post. She added, "It’s been tough recently because the world lost another legend and so many innocent lives," referring to the deaths of Kobe Bryant and eight others in a helicopter crash last week.
"You are gone but never will be forgotten," Frankel, 49, wrote. "You are missed. You are constantly quoted. You are one of a kind."
In one of the photos shared, Shields can be seen walking at the water's edge on a beach.
A high-profile banker, Shields was found dead of an apparent drug overdose in his Trump Tower apartment in August 2018. He was 51 years old.
The close friends dated on an on-again, off-again basis beginning in 2016, the same year Frankel finalized her divorce from ex-husband Jason Hoppy. Frankel and Shields' relationship, as well as his passing, was featured on several episodes of "The Real Housewives of New York City."
"You are eating multiple Nestle crunch bars, Sprites, and JG Mellon double cheese cheeseburgers in heaven, and now you have an amazing basketball player to watch and bet on up there," she continued in the birthday tribute. "You would be proud of my decisions and the evolution of my career and my life. You would be so excited about all of the announcements coming soon. You were my biggest cheerleader and were positive about a future for me that I never imagined possible."
Frankel next mentioned her 9-year-old daughter, Bryn Hoppy, writing, “Bryn is still ‘sweet as sugar’ as you always refer to her and she misses your blindfolded food tasting contests and leaving trails of chocolate chips. You were right about @biggysmallz being the greatest dogs. Bryn tells everyone: ‘Dennis has had more than 30 dogs and says he has never met sweeter dogs.’”
In the tribute, she also included her current boyfriend, Paul Bernon, whom she began dating in September 2018.
“We are in good hands with Paul, who you would like and respect and vice versa,” she wrote. “He looks out for us and is very caring. You always said I would find someone who would take care of me. We miss you. Happy Birthday! I know they have peanut butter chocolate cake and Hemingway in heaven. Everyone misses you and you are still the center of attention — just how you secretly like it. Xoxo."