And a source told Radar Shields, 51, was left with a broken heart after he bought her a ring — but never proposed on their final dinner date.
Shields died at his apartment in Trump Tower, New York on Friday of a suspected overdose.
A source told Radar: "He bought a ring and took her to dinner to feel her out, and it became obvious to him that she'd never marry. It left Dennis heartbroken."
"Bethenny could sense that he was going to ask her to marry him, and it pushed her away. So he never took it out to propose, but that was his purpose."
"He was hoping the time was finally right, but just as he got his hopes up he was shot down again, and that would be the last time sadly."
Despite the fact that he was still married to his wife, Jill, Shields and Frankel were in a relationship for two years.
A friend of the couple told Radar: "Dennis was head over heels in love with Bethenny, he died with a broken heart."
On last week's episode of RHONY Frankel announced that she was taking a break from the romance, saying: "I am going 90 days without talking to Dennis."
Shields talked about their turbulent relationship with Frankel on Mitchell Chadrow's "Listen Up Show" podcast, which had been recorded on Saturday, August 4.
"Dennis was often isolated and friends have been worried about him lately."
Friends revealed that the couple's relationship was "up and down" and this left Shields left "depressed and confused."
The source added: "Bethenny would randomly stop calling Dennis and wouldn't answer his calls for days, weeks, months, and then he'd hear from her out of the blue when he had almost given up hope.
"Dennis was always there for Bethenny but it was always on her terms, when she needed him. Dennis took her back every time, that's how much he loved her."
RadarOnline.com revealed how the cast of RHONY had been told not to comment on the Shield's shock death by bosses at BRAVO.
And, so far, there has been no comment from the Skinnygirl Cocktails mogul Frankel who was reportedly left 'devastated' upon earing of her 'on and off' boyfriend's sudden death.
The Medical Examiner is still investigating Shields death.
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at firstname.lastname@example.org, or call us at (866) ON-RADAR (667-2327) any time, day or night.
For the biggest celebrity news stories of the day, controversies, crime, and other hot topics listen to our new podcast ‘All Rise’ below!