Lauren Bacall, Humphrey Bogart were ’emotionally unfaithful’

Old Hollywood’s golden couple Lauren Bacall and Humphrey Bogart had a love story for the ages.

However, despite the two being seemingly devoted to each other during their 12-year marriage, they did engage in “emotional affairs,” according to a new book.

In “Bogie & Bacall: The Surprising True Story of Hollywood’s Greatest Love Affair,” author William J. Mann offers up surprising revelations about the storied pair.

“They did have their differences,” Mann told told Fox News. “Especially in the beginning when Bacall was struggling to be more than just Mrs. Bogart. The relationship was romantic. It was loving, it was committed. But it was not always emotionally faithful.”

Bacall was 19 when she met 45-year-old Bogart on the set of their film “To Have and Have Not” in 1944.

The “Casablanca” actor was married to his third wife, Mayo Methot, at the time. They divorced and he and Bacall wed in 1945.

Mann said that when Bacall and Bogart started dating, the budding romance “terrified” Bacall.

She was fearful of the public labeling her as the “other woman” or seeing her as a “femme fatale” — despite the fact that Bogart’s marriage to Methot was “disintegrating.”

Bronx native Bogart had his trepidations as well.

“Bogie was also very concerned. He didn’t want to lose his position in Hollywood, but he also didn’t want to lose her. In the beginning, there was a lot of nervousness,” said Mann. “But they were yearning to be together.”

The “emotional affairs” allegedly began around 1952, when Bogart and Bacall became supporters of Democrat Adlai Stevenson’s presidential bid.

In the book, Mann writes that the “Mirror Has Two Faces” actress and Stevenson “had become quite close” and “she was rarely far from his side, with Bogie somewhere in the background.”

He also insisted that her relationship with the politician was never actually physical, however “it was definitely an affair of the heart.”

Bacall and Stevenson’s friendship continued until the end of the campaign when Republican Dwight D. Eisenhower won by a landslide in November 1952.

She was reportedly “devastated” by Stevenson’s loss and even tried to stay “in touch with him” after the election.

But it was “difficult” to keep contact and it seemed like “she was more into him than he was into her.”

While she “loved Bogie,” Mann said that Stevenson had awakened “some part of herself that she had never known before.”

Bacall eventually retreated her advances.

“But in many ways, I think it was the most intense, emotional and intellectually stimulating relationship of her life,” Mann said.

Bogart had his own dalliances.

According to the author, he had an affair with wigmaker Verita Thompson that began before he met Bacall.

Thompson had crafted hair pieces for Bogart early in his career as he begun to lose strands.

Bogart and the hairstylist were “incredibly close” and had a “loving relationship.”

“They weren’t that far apart in age. … They both liked to drink — they could hold their liquor. They loved to sail. They had a lot in common,” Mann said.

Thompson supposedly hoped that Bogart would one day propose to her after separating from Methot.

But when he dumped her for Bacall, the wigmaker was hurt and “devastated.”

As time went on, Bogart and Thompson “reconnected,” and their relationship was more “likely emotional.”

“I think especially as Bacall was finding her own world, her own life, her own friends, people like Adlai, Bogie turned more and more to Verita,” Mann said.

The pair would often go sailing on his yacht and Thompson would even cut Bogart and Bacall’s children’s hair.

“She was part of the family in many ways. Bacall knew about her. I don’t think she was ever fully comfortable with her, but she knew that relationship was very important to Bogie,” he said.

Still, Bogart and Bacall were uniquely to devoted to each other

In early 1956, Bogart was diagnosed with throat cancer, likely brought on by his heavy smoking and drinking.

Bacall never left his side and became his caregiver, to the point where she would even sit with him at the hospital and “[hold] the stitches together on his abdomen” when they came apart.

“She sleeps with him when he’s about 80 pounds, because he tells her, ‘Don’t leave me tonight.’ … Of course, she doesn’t sleep all night. She’s awake,” Mann said. “You don’t do that if you don’t really love somebody. Even with the emotional indiscretions … those last several months of Bogie’s life prove how much she loved him.”

Bogart passed away from the disease in 1957.

Bacall lived to 89 and died in 2014.