A former hostage whose husband is still captive in Gaza said she does not expect to see him again unless agrees a ceasefire deal.

Aviva Siegel was freed after 51 days in captivity, under a week-long agreement last November. Her fears for her husband, Keith Siegel, were sharpened by her own ordeal of hunger, deprivation, violence, isolation and psychological torture, she said.

High-stakes talks on a deal are expected to resume on Thursday. The US president, , has been pushing for an agreement for months, but fears that the conflict in Gaza is on the brink of escalating into a full-blown regional war have added to the urgency.

The Israeli prime minister, , has been open about his preference to keep fighting until “total victory”, a divisive goal even inside Israel where his defence minister, Yoav Gallant, attacked it as “nonsense” this week.

Siegel said Netanyahu’s position was unbearably painful to her, because it was in effect a death sentence for her husband. She met the Israeli prime minister for the first time when both travelled to , Netanyahu invited to address Congress and Siegel as a guest of Biden because her husband is a US citizen.

Siegel said: “I didn’t go to his speech, to anything, to listen to what he had to say because I was scared that if I would hear that he wants to fight, it would break me into pieces, because that means that Keith will never come back.

“I can’t hear that any more, that the government wants to ‘win’ the war. I just can’t hear that any more. I pray that it will stop.”

After that speech, Biden held a tense private meeting with Netanyahu. Pictures from the start of the meeting showed the US president surrounded by relatives of hostages, including Siegel, while Netanyahu sat flanked by officials and aides.

“It was terrible. I was shocked by what I felt. I felt that Bibi isn’t understanding what the hostages are going through at all,” said Siegel, using a common nickname for the Israeli leader. There are 115 people still held hostage in , although at least a third are thought to be dead.

“When they [the hostages] do come home, they are going to ask, ‘How come we were there so long?’ What are we going to say?

“I don’t understand how Bibi goes to sleep in a comfortable bed, with clean pillows and clean sheets.”

It was a stark contrast with Biden, whom Siegel has met twice and describes as “wonderful”. He was “doing everything he can” to get hostages home, she added.

Biden himself has been increasingly open about his frustration with Netanyahu, whose coalition government is propped up by far-right parties that oppose a ceasefire. The US president reportedly told the Israeli leader to “stop bullshitting me” about a deal, and in June said there was “every reason” for people to believe Netanyahu was prolonging the war to ensure his own political survival.

Keith Siegel has now been in captivity for more than 300 days, six times the length of Aviva’s ordeal, and she says part of her is still trapped with him. “There is no ‘me’ here. I feel like I’m living for them.” The hunger, dirt, pain and violence were unbearable – she lost 10kg and was rarely allowed to shower or given a change of clothes – and the hostages were mostly barred from talking or even expressing fear or pain.

She had to watch, without crying or complaint, as captors attacked her husband and young women held captive with them. “It was so much for me to handle, and stay quiet. I felt my soul was taken away. You have to shut yourself down,” she said. “I wanted to cry, to shout, but I couldn’t.”

Once the women were forced to shower in view of their male guards, and another day to dress in skimpy outfits “like Barbies”. One, who was taken to another room on her own by a guard, later told Siegel she had been sexually assaulted.

She was moved 13 times, sometimes walking in outfits provided by their captors to disguise them as Gazans, sometimes bundled into cars. Twice they were in tunnels, one so deep underground the hostages struggled to breathe.

“You can’t talk or whisper, all you can do is try not to move,” she said. “You get to the stage where you are just lying there, thinking about your next breath, thinking this is how you will die. I prayed that I would die before Keith.”

They had no contact with the world. Their captors told them ‘there is no Israel left’, and throughout her captivity Siegel believed her son had been killed.

One woman saw demonstrations in Tel Aviv calling for hostages to be released as she walked to the bathroom, but it did not lift Siegel’s spirits. “I just said: ‘I hope my family aren’t there, as they will get hit.’”

She has seen a psychologist but has agreed they will not start treatment for trauma until her husband is free. She lives in constant fear the long captivity will kill him. “I know what he is going through and I don’t know how he can stay strong,” she said.

The two had only returned to their home in Kfar Aza kibbutz hours before the attack, after visiting Haifa in northern Israel. Keith wanted to stay there another night, and among Siegel’s layers of guilt is regret that she insisted on returning home.

The couple were attacked as they were dragged out; Keith’s ribs were fractured and he had a gunshot wound on his hand that she bandaged for weeks. When they got to Gaza they were taken to a tunnel with five other injured hostages, their clothes, the walls and floor all smeared with blood.

Siegel counts herself lucky that she was with her husband throughout her captivity and asked to stay with him in Gaza when guards said she was going to be released alone.

When they refused, she found the strength to push past a guard and give Keith a last embrace. “I told him to be strong for me and said I would be strong for him, not knowing if I would see him again.”

She made a personal appeal to Biden to do what her own government cannot or will not. “I looked at him in the eyes and told him: ‘It is your time to make history, get them all out.’”