"Trying to stay healthy & move through it w tears & close friends," Bethenny Frankel tweeted Sunday of on-off boyfriend Dennis Shields' sudden death

Celebrity Sightings in New York City - June 14, 2016
Credit: Alessio Botticelli/GC

Bethenny Frankel is getting candid about the hardships she has endured since on-off boyfriend Dennis Shields‘ death.

On Sunday — 16 days after Shields was found dead at the age of 51 in his Trump Tower apartment following a suspected overdose — The Real Housewives of New York City star, 47, expressed her sorrow on Twitter.

“It’s hard to breathe & I appreciate you giving me the space & support to try to do so,” wrote Frankel. “It’s excruciating-sudden death is no closure & constant ?s & memories.”

She continued, “Our relationship is current so it’s painfully raw. Trying to stay healthy & move through it w tears & close friends. Xo.”

BuzzFoto Celebrity Sightings In New York - December 08, 2016
Bethenny Frankel and Dennis Shields in 2016
| Credit: Josiah Kamau/BuzzFoto via Getty

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A friend of Frankel told PEOPLE three days after Shields’ death that she and her 8-year-old daughter Bryn were taking the news extremely hard.

“She is devastated,” said the source. “She loved him. He was her family and Bryn’s family. Bryn loved him. Dennis was Bethenny’s partner, her family, her business partner and her best friend.”

“He helped her with things — emotionally and professionally, and he was her confidante,” the friend added of the couple’s on-off relationship. “No question that she did love this guy.”

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In a statement to PEOPLE following Shields’ death, his wife Jill Shields said, “We are all heartbroken. Dennis was, and will always be, the love of my life. His spirit lives on in our children. Please respect our family’s privacy at this time.”

Frankel herself took to social media three days after Shields’ death, posting an Instagram photo of him cuddling with her beloved dog Cookie, who died in October at the age of 17.

“Rest In Peace my sweet babies who gave me endless unconditional love. #nowandforever,” she captioned the intimate photo.