Yago Riedijk and Ms Begum married days after she arrived inside IS territory.
Speaking to the BBC, he admitted fighting for the group but says he now wants to return home with his wife and their newborn son.
Mr Riedijk, 27, is being held in a Kurdish detention centre in north-eastern Syria.
He faces a six-year jail term for joining a terror organisation if he returns to the Netherlands.
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In an interview with the BBC’s Middle East correspondent, Quentin Sommerville, Mr Riedijk said he rejected IS and had tried to leave the group.
He told our correspondent that he was imprisoned in Raqqa and tortured after the extremists accused him of being a Dutch spy.
Describing life under IS control, Mr Riedijk also said he attended the stoning of a woman for “fornication”, saw piles of dead bodies in the city and lost an infant daughter to malnutrition.
