Heartbreaking Tearjerker of the Day: A struggling soap actor who was allegedly harassed by his neighbors and condo board into euthanizing his beloved pet pit-bull mix took his own life last week, leaving behind a note saying he was racked with guilt over “betraying” his best friend.

Nick Santino, whose acting credits include recurring roles on All My Children and Guiding Light, committed suicide last Wednesday — a day after his 47th birthday — a few hours after euthanizing his dog, Rocco.

In 2010, the management at his Upper West Side building had imposed certain restrictions on dog owners and banned the housing of pit bulls. Since Rocco had already been living in the building, he was grandfathered in and allowed to stay.

Still, Santino’s friends say he was constantly harassed by neighbors and members of the condo board who wanted him to get rid of the dog. “People were complaining about his dog,” said neighbor Kevan Cleary. “It was open season on him.” Neighbor Lia Pettigrew concurred: “Everybody knows that he had been harassed by the building management.”

After someone complained that Rocco was barking, Santino was threatened with a $250 fine. “The dog was not a barker, but somebody complained that the dog would bark,” Cleary said. “He felt like he was in this battle because he was the only guy in the building with a pit-bull mix.”

Eventually, Santino felt he had no choice but to put Rocco to sleep. After the deed was done, Santino reportedly approached the building’s doorman and handed him Rocco’s dog treats. “Give these to the other dogs,” Santino said with tears in his eyes. “Rocco is no more.”

Shortly thereafter, the troubled Brooklyn-born orphan, who grew up in foster homes and was part of 9/11’s first search and rescue team, died of an apparent pill overdose.

“Today I betrayed my best friend and put down my best friend,” Santino wrote in his suicide note. “Rocco trusted me and I failed him. He didn’t deserve this.”

Santino’s love for Rocco was well-known. Having adopted Rocco from a shelter, he sought to clarify their relationship on Facebook: “I did not rescue Rocco, Rocco rescued me.”

A condo board member who spoke with The Post refused to accept blame for Santino’s suicide. “I’m sorry the man is dead,” said board member Marilyn Fireman, “but it has nothing to do with the pet policy.”

Funeral plans for Santino are on hold at the moment. His relatives say they are waiting to receive Rocco’s cremated remains so they can be buried alongside his owner.

[post: 1,2 / imdb / gothamist.]