An incredible love story deserves an incredible ending.

That’s just what fate afforded to Isaac and Teresa Vatkin.

The Vatkins were married for 69 years, and they left behind a large, beautiful family; their children were in the room when they passed away. And that’s where this story gets amazing: The Vatkins passed away within minutes of one another.

89-year-old Teresa passed first; she’d been fighting Alzheimer’s for the past several years. Her husband, 91-year-old Isaac, passed away a mere 40 minutes later. He’d been Teresa’s caretaker and loving friend, right up until the end.

While he was still in his 80s, Isaac even ventured onto the internet in order to search for Alzheimer’s breakthroughs, according to the Chicago Sun Times. His children said that he still spoke frequently of getting an apartment with Teresa, even when her condition had advanced.

“I didn’t want them to be scared,” granddaughter Debbie Handler said in an interview with the Daily Herald. “I thought maybe if they knew the other was there, it would help.”

“His hand was on top of hers. He was trying to breathe. And then, as they wheeled her out, his hand was hanging over the bed,” said the couple’s son, Leo Vatkin. “I turned around, and he wasn’t breathing anymore…He never wanted to do anything apart from her.”

“I saw it with my own eyes,” said the couple’s daughter Clara Gesklin. “All of a sudden, when their fingers separated, he just stopped breathing.”

The children said that Isaac’s chest fell almost immediately; he was gone.

Isaac had grown up in Buenos Aires, Argentina, while his wife lived in Mar del Plata, Argentina. Mar Del Plata was an eight-hour drive from Buenos Aires when the couple met, but that didn’t deter Isaac. The couple married in 1947.

In 1968, they moved to Chicago, where Isaac quickly found work as a distributor. Eventually, he invested in apartment buildings.

“He put us through college, he paid the home off,” said Leo Vatkin. “They were never the fancy-car, the fancy-house kind of people. My dad had work ethic, honesty, doing the right thing.”

As the story of this incredible couple spread, some have wondered why Isaac was able to pass away mere minutes after his wife.

First, we’ll give you the scientific explanation.

Scientists believe that some people are able to “hold out” until they achieve certain goals—seeing a family member for one last time, for instance.

When humans are close to death, their moods can play prompt the release of chemical signals, including cortisol (created as a stress response) and oxytocin (a hormone created, in part, through positive social interactions, which opposes some of the effects of cortisol). Those chemicals can affect body processes, so achieving a goal might, technically, allow a person to “choose” when to pass.

Of course, we also love the explanation put forth by one of the Vatkins’ sons, Daniel. It might not be quite as scientific, but it’s much more poetic—and perhaps a bit more accurate.

“The moment he felt we removed her hand from his, he was able to say, ‘OK, I’m done protecting her. I can go and rest as well,’ ” said Daniel Vatkin. “The ultimate in chivalry—so he could go to heaven and open the door for her.”