An outspoken CEO known for rocking the boat resigned Thursday after the fallout from his romantic relationship with a Russian spy proved too much for investors to bear.

Patrick Byrne, the head of discount furniture seller Overstock.com, resigned Thursday — 10 days after he confirmed he’d been romantically involved with convicted Russian spy Maria Butina and that the relationship led to his involvement in the FBI’s probes of Russia and Hillary Clinton.

“Though patriotic Americans are writing me in support, my presence may affect and complicate all manner of business relationships,” Byrne wrote Thursday. “Thus, while I believe that I did what was necessary for the good of the country, for the good of the firm, I am in the sad position of having to sever ties with Overstock, both as CEO and board member.”

The road to Byrne’s resignation started on Aug. 12 when Byrne’s Overstock confirmed the accuracy of two articles by Fox News contributor Sara Carter.

One article focused on Byrne’s relationship with Butina, the Russian gun-rights activist who is serving an 18-month sentence for seeking to influence US policy on behalf of Russia. The other article said Byrne assisted the FBI with its probes into Clinton and Russia.

“In fact, I am the notorious ‘missing Chapter 1’ of the Russian investigation,” Byrne cryptically declared in Overstock’s Aug. 12 statement.

He also referred to law enforcement in his statement as “Men in Black,” and suggested that the federal probes were a farce, saying it “turned out to be less about law enforcement and more about political espionage conducted against Hillary Clinton and Donald Trump (and to a lesser degree, Marco Rubio and Ted Cruz).”

Investors balked — sending shares of Overstock down 36 percent over the next two days as investors processed Byrne’s moonlighting endeavors at the center of what MarketWatch described as “an insane Russian-spy drama.”

Byrne’s resignation, by contrast, sent the shares up 17 percent before closing at $21.12 per share, a gain of 8.3 percent.

“This latest controversy was simply one too many,” DA Davidson analyst Tom Forte told The Post. “It’s getting in the way of Overstock’s reinvention.”

Indeed, Byrne, who launched Overstock in 1999, is known for making waves and finding himself in the middle of controversies.

The CEO waged a campaign against naked short sellers in 2005, denouncing an alleged conspiracy headed by an unidentified “Sith Lord”—a reference to “Star Wars” characters who draw on the dark side of the Force — to drive down the company’s stock.

Byrne, 57, became the target of a 2011 defamation lawsuit for articles published on his “Deep Capture” Web site that accused a Vancouver businessman of working with “Osama Bin Laden’s favorite financier” and a slew of criminal syndicates.

Byrne, who has never been married, said he hit it off with Butina at a 2015 libertarian convention in Las Vegas. They stayed in touch before the relationship turned romantic during a September 2015 rendezvous at New York’s Bowery Hotel.

Butina’s keen interest in the presidential campaigns of Hillary Clinton and Donald Trump made Byrne skeptical of her, prompting him to go to the FBi, he has said.

In an interview with Fox Business after his resignation, Byrne said he came forward to law enforcement at the behest of his “rabbi,” whom he identified as billionaire investor Warren Buffett.

He said he could have received a $1 billion bribe “to be quiet,” but that didn’t appeal to his self-image as a “flag-waving hippie like Jerry Garcia,” of the rock band the Grateful Dead. Byrne then waved a MAGA-like hat emblazoned with the words, “Make America Grateful Again,” a reference, presumably, to the deadhead band.