The co-founder of movie ticket firm Fandango left a heart-wrenching suicide note confessing he “can’t explain the pain” — before leaping to his death from a luxury hotel in Midtown Manhattan, law enforcement sources said Thursday.

“So sorry. I can’t explain the pain of f— up this much. I love you all,” J. Michael Cline wrote in the letter, with some apparent missing words, the sources confirmed.

The 64-year-old “serial entrepreneur” and father of six left the devastating final message, first reported by TMZ, in Room 28 of the Kimberly Hotel on East 50th Street near Lexington Avenue, sources said.

Cline jumped from the 20th floor and landed in a third-floor courtyard Tuesday morning, authorities said.

His suicide stunned and gutted people who knew him, and happened just days after he underwent gallbladder surgery, sources said.

Cline owned multimillion-dollar homes in Greenwich, Connecticut, and Palm Beach, Florida, including a lakefront manse he bought with his wife, Pamela, for $20.75 million in December 2020, according to the Palm Beach Daily News.

He had years ago cut ties with Fandango, which struggled as ticket sales plunged during the pandemic.

Cline was managing partner at the startup funding firm Accretive and had founded multiple other companies over the years.

Cline, who graduated from Cornell University and got an MBA from Harvard University, was described in a recent Fordham University article as a “serial entrepreneur” who inspired students to dream big and “work with people you trust.”

People struggling with suicidal thoughts can call or text the Suicide Crisis Lifeline at 988 for support.