The illness — IgA Nephropathy, a debilitating disease his doctors believe was triggered by months inhaling toxic dust at Ground Zero and the Fresh Kills landfill after the Sept.11 terror attacks — forced Volpe to exit the force in 2004, his career and dream of starting a family crushed.

In 2013, on the day doctors told Volpe his kidneys were failing, he gave then-fiancee’ Angela, who also wanted kids, his blessing to break up.

“So I gave her the out, I said, ‘Angela, you’re young. You don’t need to live a life like this,’” he told The Post. “She looked me right in the eye, and she said, ‘I love you, and I’m marrying you, no matter what.’”

That love – and a generous stranger – helped the couple survive their darkest days.

An article in The Post about the hero cop’s rare disease prompted a big-hearted reader to anonymously donate a kidney, saving Volpe from dialysis, a grueling regimen that usually shortens lives.

That gift has kept him alive to this day.

Following the transplant, the newlyweds had to wait a year before trying to conceive while the post-op medication – which might cause infertility or birth defects – wore off.

But it worked. Gianna, now 10, was born in 2014.

“I think it was a miracle baby,” Volpe said.

Baby sister Sofia arrived three years later.

“My girls adore him,” Angela said of their doting dad. “He’s there for everything, all their sports andschool stuff. We do everything together as a family.”

Volpe, now 58, takes loads of medication for his kidney, asthma and sinus problems contracted after 9/11.

Transplanted live-donor kidneys typically last up to 20 years or so, and Volpe worries he may need another one soon.

Volpe, now 58, takes loads of medication for his kidney, asthma and sinus problems contracted after 9/11.

“I want to be around, hopefully, to see my kids get married,” he said. “That would be awesome.”

Volpe’s plight is compounded by the World Trade Center Health Program’s failure to investigate whether IgA Nephropathy – aka “Berger’s Disease” – should be added as a 9/11 condition covered under the Zadroga Health and Compensation Act, which would entitle him to federal aid.

Researchers have found 24 cases of the rare kidney disease reported by 9/11 first responders.

“We think we have seen five to 10 times more of this illness than we would expect to see in the general population,” said Ben Chevat, executive director of 9/11 Health Watch, an advocacy group trying to focus attention on the problem.

Dr. Alan Coffino, Volpe’s former kidney specialist, believes toxins in the respiratory system can trigger the ailment: “I’m highly suspicious that his Ground Zero exposure is the cause,” Coffino said when Volpe’s kidneys failed.

Two other Ground Zero ex-cops, Robert Joseph Martin and John Muldoon, also contracted the disease — which usually hits people in their 60s or 70s — in their early 30s, and went into kidney failure around the same time in 2013 and 2014.

“That’s not a coincidence – 12 years after 9/11, three police officers get kidney transplants six to seven months apart,” Martin, 54, told The Post.