You know how Trump treats even people close to him like shit? Maybe it’s going to bite him in the ass now.

For years, a joke among Trump Tower employees was that the boss was like Manhattan’s First Avenue, where the traffic goes only one way.

That one-sidedness has always been at the heart of President Trump’s relationship with his longtime lawyer and fixer, Michael D. Cohen, who has said he would “take a bullet” for Mr. Trump. For years Mr. Trump treated Mr. Cohen poorly, with gratuitous insults, dismissive statements and, at least twice, threats of being fired, according to interviews with a half-dozen people familiar with their relationship.

“Donald goes out of his way to treat him like garbage,” said Roger J. Stone Jr., Mr. Trump’s informal and longest-serving political adviser, who, along with Mr. Cohen, was one of five people originally surrounding the president when he was considering a presidential campaign before 2016.

Now, for the first time, the traffic may be going Mr. Cohen’s way. Mr. Trump’s lawyers and advisers have become resigned to the strong possibility that Mr. Cohen, who has a wife and two children and faces the prospect of devastating legal fees, if not criminal charges, could end up cooperating with federal officials who are investigating him for activity that could relate, at least in part, to work he did for Mr. Trump.

May it prove true.

Trump has always felt he had leverage over Cohen, but his goons say the raid has flipped that.

For years, Mr. Cohen has described himself as unflinchingly devoted to Mr. Trump, whom he has admired since high school. He has told interviewers that he has never heard Mr. Trump utter an inaccuracy or break a promise. He has tweeted about Mr. Trump nearly 3,000 times.

In a Fox News interview last year, Mr. Cohen declared: “I will do anything to protect Mr. Trump.’’ He told Vanity Fair in September that “I’m the guy who would take a bullet for the president,” adding, “I’d never walk away.”

Over the years, Mr. Trump threatened to fire Mr. Cohen over deals that didn’t work out, or snafus with business projects, people who were present for the discussions said. He was aware that Mr. Cohen benefited in other business projects as being seen as affiliated with the Trump Organization, and it irked him.

Which is funny, when “the Trump Organization” itself is what it is only because of Trump’s gigantic tower of lies.

But this part is really sad: Trump loves Lewandowski more than Cohen. A lot more.

Particularly hurtful to Mr. Cohen was the way Mr. Trump lavished approval on Mr. Lewandowski in a way he never did for Mr. Cohen. When Mr. Cohen told Mr. Trump that he believed that Mr. Lewandowski had been behind a negative story about Mr. Trump’s son-in-law, Jared Kushner, Mr. Trump dismissed the comments as simple jealousy, and didn’t pay attention, according to two people familiar with the incident.

Aw. Ouchy.