The young mom whose ex-con husband gunned down a Bronx NYPD sergeant said the tragedy has left her completely shattered, but she is desperately trying to hold it together for the sake of her sweet little boy.

In a wide-ranging, and at times tearful, two-hour interview with The Post, Tia Rosales opened up about how the events of Nov. 4 have torn her world apart.

Rosales said she feels devastated for the slain officer’s widow, Lisa, and sons Austin, 4, and Joseph, 3 — and fears her own son, 3-year-old Tony, will forever be known as the son of a cop-killer.

“I certainly feel a tremendous sadness for her, that she has to share in this pain,” Rosales, 29, said of Sgt. Paul Tuozzolo’s widow.

Manuel Rosales was killed by officers in his SUV after fatally shooting Tuozzolo.

The 18-year-veteran and several other officers were responding to a call Tia’s friend had made, saying Manuel had forced his way into her Bronx apartment with a gun and threatened to kill both women.

Rosales said she is still trying to figure out when and how to tell Tony what happened that day — and worries about the stigma he will face.

“I don’t want my son to go through life known as the son of a cop-killer, that is a horrible thing to live with,” she lamented during the interview at her East Setauket, LI, home.

“My wish would be, too, that while he is young, to shelter him from all the bad, and let him see the happy photos and share with him how much his father loved him, because he did love him.”

‘I don’t care what anybody says, there is no difference between the officer’s children and my child. They are young, innocent boys, who all lost a father.’ - Tia Rosales

But she knows that one day, she’ll be forced to tell him the brutal truth.

“When he’s older and ready and wants to know, I will have to tell him,” Rosales said.

She also fears her husband’s murderous actions will continue to haunt her family for years to come.

“My biggest worry is what my son and the rest of my family might go through in the future because of it,” Rosales said. “We all share the same last name.”

The widow has already been attacked online for the cop killing, with outraged strangers slinging threats at her on Facebook, she said.

“There are people outright saying, ‘Screw your kid, nobody cares about him,’ ” Rosales explained.

“I don’t care what anybody says, there is no difference between the officer’s children and my child. They are young, innocent boys, who all lost a father. It is not simply bad guys vs. good guys, they’re children.”

Rosales recalled the day of Tuozzolo’s murder, saying she thought she’d found a safe place to stay with a close friend. But Manuel, who’d abused her several times in the past, showed up at the door with a gun.

“He said, ‘I’m here for my son,’” she recalled. “I said, ‘You can’t take him,’ and he said, ‘And I’m taking you too.’”

Days later, she would discover that Manuel had been stalking her, even sleeping on the roof as he waited for his moment.

In his rage, Manuel attempted to forcibly remove them from the apartment, but Tia’s friend calmed him down and cooked him breakfast.

Despite the “weird” and “aggressive” situation they were in, Tia was grateful her son was able to spend a few hours with his father.

“He left very, very sorry,” she said. “He was on his knees begging for forgiveness.”

Manuel eventually left after Rosales’ pal promised him she wouldn’t call the cops.

“Of course, after he left we called the police, and we were very worried,” she said.

They knew something terrible had happened when they heard shots fired on the street minutes later.

“We heard like 20 gunshots, and we knew either he was killed or someone got hurt,” Tia said.

“It’s hard to imagine him pulling out a gun and shooting a cop in the head. The whole thing seems like a dream.”

Rosales claims the tragedy could have been avoided if only a Suffolk County judge had set a higher bail when her husband was arrested in July for beating her in their car.

The Suffolk DA’s Office asked for $20,000 bail, but the judge set it at $1,000, she said.

“Being that he had violent tendencies, he shouldn’t have,” Rosales said. “He was calling out for help, but each time he got out of jail, it was left entirely up to him.”

Rosales insisted that Manuel, who suffered from bipolar disorder and schizophrenia, could have controlled his violent urges if he’d received therapy and attended anger management courses. Manuel was suicidal, she said, and had threatened “suicide by cop” before.

“He needed psychiatric help and when he asked his parole officer, she said to go to social services, but they did nothing,” she said.

“Integrating back into society proved too overwhelming for him. He needed help and it wasn’t available for him. I believe if he had gotten psychiatric help, this would have never happened.”

Rosales said the only way she copes is by speaking out about mental health issues.

“There were a number of times I was willing myself to wake up,” she said. “The pain was just desperate, horrible.”

Rosales said she even has “tremendous regret” for not telling Manuel she loved him before he left the apartment on that fateful day.

“I just want people to understand that he wasn’t a monster, a maniac,” she said. “He was a human being, he was a father and in his moments of clarity, he was very kind and loving.”

Last week thousands of cops lined the streets to say goodbye to Sgt. Tuozzolo: