Bethenny Frankel's boyfriend cause of death: Dennis Shields found dead in Trump Tower

Dennis Shields, Real Housewives of New York City star Bethenny Frankel's on-again, off-again boyfriend, was found dead at the Trump Towers in New York on August 10, Friday.

The 51-year-old was found unconscious and unresponsive in an apartment on the 42nd floor at 9:30 am, ABC News reports. He was declared dead at around 10:15 am.

While the officials haven't officially released the cause of death, TMZ and New York Post report that he suffered an apparent overdose. Sources close to the case told the publications that he could have possibly died of OxyContin overdose.

Shields reportedly fell unconscious after he asked his assistant to administer Narcan — an emergency antidote which is used to reverse opioid overdose. The medication couldn't revive him.

Although Frankel is yet to break her silence over the death, a source told E! News that she is "heartbroken" by the news of Shields' sudden death. "This is really bad. It's dreadful. She's known him for over 20 years," the insider revealed.

"Bethenny loved him a great deal but it was an unusual relationship," another source told People magazine. "They were on and off. It was unconventional and not always exclusive. They would be together and then not. Sometimes these traditional relationships aren't the best thing for everybody."

"Dennis was a steadying rock for Bethenny. He was very mild-mannered and she is like a force of nature but she needed that in him," the source added.

Shields' estranged wife Jill Schwartzberg Shields also issued a statement expressing her thoughts about his sudden demise. "Dennis' family is devastated by this terrible news. He was a loving father and friend. We ask that the media respect our privacy during this time of loss," she said in a statement.

Shields had four children with Jill: daughters Tyler, 24, Darien, 20, and Kelsey, who is in college, and one son, Zachary, 23.