The 36-year-old actress had been dating the 34-year-old actor – whose divorce from Scarlett Johansson was finalized in June – for two months, but he has called time on their romance because he didn't want any serious involvement.
A source said: "He only wanted something casual, but she's in a rush to settle down, have kids and start a family since she's getting older.
"Charlize didn't take it very well when he broke it off. She knows deep down that it wouldn't have worked, but she is pretty bummed out about it all."
A friend of Charlize – who ended her nine-year relationship with Stuart Townsend last year – blamed their conflicting schedules for her split from Ryan.
The insider told Us Weekly magazine: "They're both too busy. And they were hardly ever together anyway."
Ryan recently admitted he is still not over the ending of his marriage to Scarlett, who he split from last December.
The 'Green Lantern' star said: "At the moment I'm just giving myself time to put everything that has happened behind me and I'm taking things as they come. But I'm going to be ready for a relationship again soon."