Killian Roche, who proposed to Emily only two months ago, collapsed at a hotel in the Gulf city on Saturday.
It is understood he fell ill in the lobby and later died.
Consular assistance is being provided to the family following the tragedy.
“The Department of Foreign Affairs and Trade is aware of the case and providing consular assistance,” a spokesman told Independent.ie last night.
The couple got engaged in February, with Emily announcing the news on her Instagram account.
“My best friend asked me to marry him tonight and I said YES,” she told her 10,700 followers.
She also uploaded a picture of her and Killian with the engagement ring.
Killian announced the news on his Facebook page with a photo of the couple kissing, saying: “Today Emily MacKeogh made me the happiest I’ve ever been.
“Thank you so much and I’m so happy that you said yes.”
Killian popped the question while the couple were enjoying a getaway in the Swiss city of Zurich.
He died only days after the couple had moved to the United Arab Emirates to start a new life together.
“Killian died on Saturday,” a source said.
“Emily is absolutely devastated. We are hearing it was either sudden adult death syndrome or a heart attack, but the autopsy is being carried out.
“Killian wasn’t unwell, there was nothing wrong with him. It’s such a tragedy.”
Emily (32) shot to fame when she was added to the cast of RTE reality show Fade Street in its second season alongside Roz Purcell.
She continued to model after the show wrapped and went on to set up her own jewellery businesses, Roxluna and Crystal and Co.