According to a source "they want to make it official as soon as possible."
Mavrakis was seen out not wearing her wedding ring and then the married couple announced their breakup.
McGregor's wife admitted the end of her 22 year marriage to the Trainspotting star was "disappointing."
The Phantom Menace actor filed for divorce from Mavrakis in Jan. 2018.
Now, he and Winstead are determined to settle down together, the insider told RadarOnline.com.
"Once Ewan's affairs are settled with his soon-to-be ex-wife, his plan with Winstead is to slip away and tie the knot.
'Mary Elizabeth is pushing the relationship to be as close to a marriage as possible, by her own admission, and is now at the point where she hates even spending a single night away from Ewan."
Fans were shocked when married McGregor took up with much younger Winstead, and his daughter Clara certainly doesn't approve!, as RadarOnline.com reported.
She slammed her father’s new girlfriend after a fan account posted a photo of her naming her the "most beautiful and talented woman on earth."
Clara ranted back, "Most beautiful and talented woman on earth? Oh man y’all are delusional. The girl is a piece of trash."
- 50-Year-Old Ewan McGregor Welcomes Secret Baby With 36-Year-Old Girlfriend Mary Elizabeth Winstead Only One Year After Finalizing His Divorce From Ex-Wife Eve
- Ewan McGregor & Girlfriend Mary Elizabeth Winstead Buy Love Nest Amid Actor’s Divorce
- Ewan McGregor Claims He's 'Happier' After Romance With Mary Elizabeth Winstead
But that isn't stopping McGregor and his actress beauty, the source told RadarOnline.com.
"Mary Elizabeth wants a family with Ewan and their commitment is stronger than ever, but the next step is getting married, and that's something she tells friends they both want very badly.
"Unfortunately, both she and Ewan are booked pretty solid for the next year with movies, and they want to be married a lot quicker than that, really, as soon as possible."
The source added, "Even though this relationship had a very tumultuous start, they're on solid ground and make for a very devoted couple."
We pay for juicy info! Do you have a story for RadarOnline.com? Email us at email@example.com, or call us at (866) ON-RADAR (667-2327) any time, day or night.
Get the exclusive celebrity scoop on all the stars you love before any of your friends by subscribing to our new podcast Straight Shuter below!