(CNN) About a month before Michael Cohen released his recording of a sensitive conversation he had with Donald Trump, the President's longtime attorney and adviser was agonizing over the silent treatment he was getting from his former boss.

"I don't understand why no one's calling me. I don't understand why no one's communicating with me," Cohen told Bo Dietl, a longtime friend and well-known private investigator who relayed the conversation to CNN.

Federal prosecutors were bearing down on him over his business dealings, some involving Trump, and Cohen was looking for a sign of reassurance from the President, a man he regarded more as family than as a boss.

"He was very taken aback that no one was communicating with him," Dietl said. "You're so close to somebody and all of a sudden they stop talking to you, you wonder what's happened."

Over the next month, Cohen began sending up flares, signaling that he was considering cooperating with federal prosecutors and that his ultimate loyalty would be not to Trump, but to his "family and country."

The rupture with his former boss was a startling shift for Cohen, who enjoyed nearly daily access to Trump and his entourage for more than a decade during which he served as Trump's fixer, political adviser and fiercest public defender.

Cohen's friends and associates said that as he has fallen deeper into legal trouble this year, the New York lawyer still held onto hope that he would receive Trump's support. He was "looking for a sign" from the President or others around him that his longtime boss had his back, and became increasingly distraught as he realized help wasn't coming.

In fact, one thing after another -- Trump publicly minimizing Cohen's work for him over the years and brashly predicting Cohen would never "flip" ; Trump's lawyer, Rudy Giuliani, saying Cohen has no valuable information about Trump -- indicated to Cohen that he had, in fact, been "left on his own."

And then on Tuesday night, Cohen authorized his lawyer, Lanny Davis, to release a recording indicating that Trump knew about payments made to keep former Playboy model Karen McDougal's allegations of an affair with Trump out of the public eye.

Trump fired back on Twitter by asking: "What kind of a lawyer would tape a client? So sad!"

What kind of a lawyer would tape a client? So sad! Is this a first, never heard of it before? Why was the tape so abruptly terminated (cut) while I was presumably saying positive things? I hear there are other clients and many reporters that are taped - can this be so? Too bad! — Donald J. Trump (@realDonaldTrump) July 25, 2018

Cohen referred questions to Davis, who did not respond to requests for comment on this story.

The release of the sensitive, private conversation was a stunning betrayal for a man who has prided himself over the years on his reputation as Trump's pit bull and who once said he "would take a bullet" for Trump.

The remarkable about-face followed a year-and-a-half during which Cohen had grown increasingly estranged from Trump since the real estate mogul moved into the White House, leaving Cohen behind in New York with the title -- but little of the responsibility -- of personal attorney to the President and progressively dwindling access.

Cohen quickly became embroiled in questions about Trump's ties to Russia and Russian interference in the 2016 campaign. Trump was advised to limit contact with his longtime consigliere. The President's family and entourage also limited their interactions with Cohen.

Sources close to Cohen said the limited contact fueled a sense of isolation, particularly as he lawyered up to face congressional committees and federal investigators looking into matters stemming from Russian interference in the 2016 election and questions of collusion with the Trump campaign.

But Cohen's biggest mistake may have been his belief that his relationship with Trump amounted to more than employee-employer, two sources familiar with their relationship said.

"No matter how close your relationship is, you're always staff. And anybody that doesn't get that, you're on a path toward no good," one source said.

"The highway is littered with Trump lieutenants who made the mistake of believing that," said a second source.

Cohen's belief was perhaps fueled by his standing as a jack-of-all-trades, a self-described "fixer" for Trump who managed everything from real estate branding deals and hush money payments to assembling a diversity coalition during the 2016 campaign.

During the campaign, Cohen's media appearances became notorious for his Trump-can-do-no-wrong style and his threatening tactics with reporters became well-known. Cohen once infamously cautioned a reporter to "tread very f*****g lightly ."

Those who have known Trump for years said Cohen was a constant presence by his boss' side and eager to use the Trump name around New York.

John Catsimatidis, the billionaire businessman and prolific donor who ran for New York mayor in 2013, said he remembers Cohen reaching out shortly after Catsimatidis announced his mayoral bid. There was only one reason he agreed to a breakfast meeting, Catsimatidis said: because Cohen name-dropped Trump.

"I didn't know what he wanted me for before the breakfast and I didn't know what he wanted after breakfast. It was a very confusing breakfast, I can tell you that," Catsimatidis said. "The only reason I took the breakfast is because he put himself out there and said that he worked for Donald Trump."

One Republican source intimately involved in New York politics told CNN that it was Cohen who called him in 2013 to pass along the message that Trump was interested in running for governor. This person said he subsequently ran into Cohen from time to time, and simply viewed Cohen as the "guy who was there at Trump Tower."

But in the run-up to the 2016 election, it seemed clear that whatever Cohen's role had been in managing Trump's political career up until that point had diminished, sources said.

Sources close to Trump speculated that Cohen's release of the tape was his latest attempt to show Trump he means business and is prepared to provide prosecutors with damaging information about his former boss -- but they also said it was the wrong strategy, and that it was unlikely to make Trump eager to help Cohen legally or financially.

It's unclear if Cohen has any legally damning information to provide special counsel Robert Mueller about Trump. But the public breakup has only ramped up the speculation that Cohen will "flip" on the President.

Davis said Cohen felt the need to defend himself.

"I completely understand why under ordinary circumstances prosecutors would not approve of what I did," Davis said in a separate interview Wednesday. "But I believe they would at least understand that I had an obligation to my client to correct the record on something harmful to him."

Mark Cuban, the billionaire businessman who was spotted dining with Cohen more than once in New York City last year, told CNN that Cohen has mostly talked to him about his hopes of writing a book and about his son's baseball career.

"I don't know anything, but if I had to bet I would say he tells the truth," Cuban mused. "He loves his family. He won't want to be away from them."