Former Lance Corporal Chris Harris, 41, was in newly liberated Raqqa when it is believed he triggered a device linked to infra-red sensors.
Mr Harris, of Hockley, Essex, married wife Claudie, 34, in August and yesterday she was too upset to speak.
A source told The Sun: ‘He was well respected and liked by everybody.’
Mr Harris, whose Facebook page has been turned into a memorial, spent nearly 20 years in 01 EOD Regt of the Royal Engineers.
He served in Kosovo, Iraq and Afghanistan before leaving in 2014.
When he died on Tuesday, he was working as a contractor for engineering firm Tetra Tech on behalf of the US State Department.