Islamic Sate fighter Yago Riedijk, 27, who is being held in a Kurdish-run detention centre in northern Syria, married Ms Begum when she was 15 after she ran away from her home in Bethnal Green, east London to join ISIS four years ago.
In an interview with The Times, Riedijk, who is from the Netherlands, said the couple are living a “nightmare” after the death of their third child – a baby son who was born in a Syrian refugee camp in February. The baby was less than three weeks old when he died.
The couple’s first two children, a girl and boy, died of malnutrition as infants.
“She was devastated,” Riedijk told the newspaper. “Me and her, we loved them so much it’s a nightmare. It’s the worst thing that could ever happen.”
He also recalled how “easy” it was to love Ms Begum. “We got very close very quickly. She was the perfect wife. She was so young and innocent,” he said.
Riedijk said it was “ridiculous” to suggest his wife had a deeper role within Isis and said she barely left the house apart from when he took her to the park or the market.
Riedijk was found by the BBC in the detention centre in Syria in early March and told the broadcaster that he wanted to return to the Netherlands with Ms Begum and be a family.
The pair fled Baghouz, the group's last foothold in eastern Syria, as its territory collapsed in recent months.
Riedijk, who ended up in the detention centre after surrendering to Syrian fighters, faces a six-year jail term for joining a terror organisation if he returns to the Netherlands after being convicted in his absence in summer 2018. His Dutch citizenship has not been revoked. Ms Begum has been stripped of her UK citizenship by the Home Office to prevent her from returning to London.
Ms Begum fled to the al-Hawl refugee camp from Baghouz around the same time as Riedijk surrendered to the Syrian fighters but she has since reportedly moved on elsewhere as she feared for her life.
It is said that her recent “fame” had angered a lot of the other wives in the camp and that she was taken to another base in Syria after she was “threatened.