The Dutch husband of Shamima Begum says he wants to return to the Netherlands with her and their newborn son.
Islamic Sate fighter Yago Riedijk, 27, is being held in a Kurdish-run detention centre in northern Syria.
Begum was 15 when she ran away from her home in east London to join Islamic State in 2015. The pair married before she had turned 16 and Riedijk was 23.
Riedijk, who said he rejects Isis, was found in the detention centre by the BBC.
In an interview, he said he had been imprisoned in Raqqa and tortured after the extremists accused him of being a Dutch spy.
He and Begum, now aged 19, escaped from the town of Baghouz, the group’s last territory in eastern Syria, as its territory collapsed in recent months.
Riedijk surrendered to a group of Syrian fighters, while the heavily pregnant Begum ended in the al-Hawl refugee camp in northern Syria, where she was found by a Times journalist.
She gave birth to their newborn son, Jarrah and both have now reportedly been moved elsewhere.
According the the family’s lawyer, Tasnime Akunjee, the teenager and her son were moved from the Al-Hol camp due to “safety concerns around her and her baby”.
In a separate interview with Sky News, he said they had made a mistake by joining the terrorist group.
He said: “I know (Shamima) is not a danger to anyone but she made a mistake and she’ll have to live with the consequences.
“She never really did anything besides being a wife.”
Riedijk said Shamima was a good Islamic wife who stayed in the house and took care of him and their children.
He said: “I hope our governments can see that I really made a mistake and very much regret what I did, that I lived a very miserable life in Islamic State and want to better myself and hopefully return to life as it once was.”
He added: “Wherever she goes, I’m going to go.”
Asked by the BBC if he thought marrying a girl of that age was acceptable, he said: “To be honest, when my friend came and said there was a girl who was interested in marriage, I wasn’t that interested because of her age, but I accepted the offer anyway.
“We sat down and she seemed in a good state of mind. It was her own choice, she was the one who asked to look for a partner for her.
“Then I was invited and yeah, she was very young and it might have been better for her to wait a bit. But she didn’t, she chose to get married and I chose to marry her.”
Begum, who has said she wants to return to the UK, has been stripped of her British citizenship.
Her family intend to challenge the decision.