Then in 2017, things changed.
He was no longer thanking Mavrakis in his award acceptance speeches. Now he was thanking his new partner, American actor Mary Elizabeth Winstead.
And over the weekend, McGregor married Winstead in a "small wedding for close family and friends".
Here's everything we know about McGregor and his relationships.
Watch: Ewan McGregor thanks wife and girlfriend at 2018 Golden Globes. Post continues below.
McGregor's love story with his first wife Eve Mavrakis began with a meet cute on set.
Back in the 1990s, when the Scottish actor's career was just starting to take off, he had a minor role in the series Kavanagh QC. French-born Mavrakis, five years older than him, was the production designer.
"I knew right then that I really wanted to be with her," McGregor later told The Graham Norton Show.
"I knew I wanted to be with her in a different way to all the other many, many, many women I had been with up until that point. And I wasn’t wrong. I made the right choice."
The couple married in 1995, and, just seven months later, had their first child, Clara. McGregor and Mavrakis had three more children together - Esther was born in 2001, and Anouk ten years later. In between, the couple adopted Jamyan, an orphan from Mongolia.
McGregor had met Jamyan while riding his motorbike through Mongolia with Charley Boorman for the series Long Way Round. Back then, she was just two years old.
"We went to a street shelter for children and we were both massively moved by it," he explained in Long Way Up. "We left that day, but I couldn't stop thinking about that little girl. It took nearly two years, but eventually, we adopted Jamyan."