Fabulous at 54! Carole Radziwill's Beau Adam Kenworthy Posts Racy Birthday Tribute to 'RHONY' Star

They may have an unconventional relationship, but Adam Kenworthy wasn’t shy about showing off his affection for Carole Radziwill on her birthday.

The Real Housewives of New York City star turned 54 on Sunday and Kenworthy took a moment to send her his own special birthday wishes: two photos of Radziwill, including a rather racy one of her flashing her bare chest in a rash guard and bikini bottoms. (Both photos were taken during the duo’s vacation back in March to Little Palm Island Resort & Spa in Little Torch Key, Florida.)

“HBD @caroleradziwill,” he captioned each post with a heart emoji. “#54.”

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The Bravo star was previously married to Anthony Radziwill, John F. Kennedy Jr.‘s maternal cousin and best friend, from 1994-99. The late TV executive died at the age of 40 after a battle with cancer.

In recent years, Radziwill has been seeing 32-year-old Kenworthy, who is a chef — but the two sparked breakup rumors earlier this month after she unfollowed him on Instagram.However, a source close to the Bravo star told PEOPLE last week that it’s not that simple.

“They took a break — but they still spend a lot of time together,” said the source. “It’s still unclear. It’s not black or white.”

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That being said, they didn’t appear to celebrate Radziwill’s birthday together: She spent the weekend in the Hamptons, while Kenworthy remained in New York City, according to each of their Instagram stories.

“The truth is they have an unconventional relationship,” the source told PEOPLE last week. “And they’re in an in-between stage.”