The Big Little Lies star, 30, and Green Bay Packers quarterback, 38, broke up about a year after getting engaged, a source confirmed to E! News on Feb. 16. As the insider exclusively tells E! News, "it didn't work out" for the busy couple.
But why? Though Shailene previously called her ex-fiancé a "wonderful, incredible human being," it seems they've been growing apart in recent months.
"They are two very different people," explains the source. "They are both focused on their careers but it took them in separate directions."
As for where the former lovers stand now, the source adds, "They remain supportive of one another and on good terms."
If you need any more proof of their amicable dynamic, look no further than Aaron's Instagram. Last week, he seemed to hint at big changes in his life by saying, "I'm thankful for all the highs and lows this year and the growth opportunities on and off the field. Thank you for all the love and support."
None other than Shailene showed some encouragement by liking her ex's post, which came after he earned his fourth Associated Press MVP at the NFL Honors ceremony.
E! News reached out to their reps for comment and has not heard back.
While the breakup may come as a surprise to fans, Aaron previously shared that the pair was planning to spend four months apart to focus on their separate careers.
"It's a busy work time for her," Aaron told Haute Living in September, referring to her filming schedule.
He added of his choice to focus on football, "[My decision] probably came at a good time for both of us to be able to focus on our work," explaining, "I think it's going to be a good thing. I mean, her work was shut down for an entire year, and she's booked a number of projects. She enjoys working and her own routine, which I obviously enjoy, too."
At the start of their relationship last year, Shailene revealed on Jimmy Fallon's show that it wasn't Aaron's talents with the ball that first attracted her.
"I didn't really grow up with sports, especially American sports. It was never really on my radar," she recalled. "I don't know him as a football guy. I know him as, like, the nerd who wants to host Jeopardy!. That's the dude I know."
Soon after, in February 2021, the athlete announced they had recently gotten engaged. "2020 was definitely a crazy year filled with lots of change, growth, some amazing, memorable moments," he said at the time. "I got engaged, and I played some of the best football of my career."
Take a look back at some highlights from their relationship below.