This news is yet another jolt in the family members' agonizing journeys of hope, anger, despair and uncertainty over the past 509 days.
"My heart has been in my throat for most of the day," said Sarah Bajc, an American woman whose partner, Philip Wood
, was on Flight 370.
A source close to the investigation told CNN that Boeing officials believe they are seeing a wing component of a 777 aircraft in the photos of the debris found off the coast of the French island of Reunion.
But Bajc and other family members of passengers who spoke to CNN about the developments said they remained very wary of jumping to conclusions.
"It may be the debris of MH370, but I think I'd rather wait for the official confirmation," said Steve Wang, a Chinese man in Beijing whose mother was on the flight. "We've had so many false alarms since the plane went missing."
Family members have had to contend with all manner of leads in the search for MH370 that turned out to have no connection to the plane.
They included reported sightings of debris in the South China Sea and Indian Ocean as well as pings that were initially thought to possibly be emanating from the missing plane's submerged black boxes.
Bajc told CNN's "Anderson Cooper 360˚" that her initial response to such developments "is to disbelieve it until there's some kind of verification, because there's been hundreds of these false claims along the way and it's just too exhausting to try to track all of them."
'That little thread of hope'
So far, no confirmed trace of the missing jetliner has been found since it disappeared en route to Beijing from Kuala Lumpur, Malaysia.
That has left many family members holding on to hopes
, however slim, that their loved ones are still alive.
But that could change if the debris found off Reunion turns out to be from MH370.
"If ultimately this is a piece of the wing, then that little thread of hope that I have been holding on to will have to break. And reality will have to take over," Bajc said, choking back tears.
Wood, her partner, was an American IBM executive who boarded Flight 370 to return to Beijing, where they both lived at the time. The couple were about to move to Kuala Lumpur and were going to get married later that year.
Jacquita Gonzales, the wife of Patrick Gomes, the inflight supervisor on the flight, expressed similar feelings to Bajc.
"I am torn," she told CNN. "If it is confirmed to have come from 370, there will be some closure for us, but I am also hoping it's not the plane -- that Patrick is still alive."
More questions than answers
The discovery of the object off Reunion also does little to answer many of the burning questions that family members have been asking since the aircraft vanished.
"Where's the plane? Where are passengers? And what really happened? Why might something have happened? Who's responsible?" said K.S. Narendran, an Indian man whose wife of 25 years, Chandrika Sharma
, was a passenger on the flight.
Malaysian authorities, who are in charge of the investigation, have so far been unable to establish why the plane veered dramatically off course and apparently ended up in the Indian Ocean.
Confirming that the debris found Wednesday is from Flight 370 would only provide "a very small piece" of a complicated picture, Narendran told CNN's "Erin Burnett OutFront" from his home in Chennai, India.
"To me, it raises more questions than it answers at this point in time," he said.
'It's just been such a roller coaster'
Sharma had left Chennai on the morning of March 7. Working as the executive secretary of the International Collective in Support of Fishworkers, she was on her way to Mongolia for a United Nations conference. She was to return by the 15th.
"It's just been such a roller coaster over the months," Narendran told CNN.
He said he found it "a little hard to believe" that part of the plane could be found thousands of miles from the remote area of ocean far off the coast of Western Australia where authorities say they believe the plane went down.
But Australian officials who are leading the huge underwater search in that region say they believe that currents could have taken bits of the plane to the other side of the Indian Ocean.
"If in fact it is airline wreckage, it is consistent with the area that we are searching at the present time, and is in fact consistent with calculations that have been made, in relation to the likely resting place from MH370," said Australian Deputy Prime Minister Warren Truss told Nine Network Australia.
But he cautioned that if the debris is determined to be from Flight 370, it's "not really going to be all that helpful in pinpointing precisely where the aircraft is."
In the meantime, families have nothing they can hold on to as evidence of what became of their loved ones.
"There's no proof of death, there's no substance to even show what had happened," Bajc said. "It's just a giant black hole."