Gerard Butler reportedly regrets "not treating Jessica Biel with the respect she deserved".
Jessica and her long-term on-and-off beau Justin Timberlake married in Italy last month.
While Jessica and Justin were temporarily broken up, Gerard enjoyed a summer fling with the actress during filming of their romantic comedy Playing for Keeps in 2011.
Apparently Gerard was spooked when Jessica was pushing for something more serious.
He feels remorse for his decision to call it quits.
"Gerard doesn't have many regrets but not treating Jessica with the respect she deserved while they dated is one of them," a source told Radar Online.
"He genuinely believes she was the one that got away.
"Jessica liked Gerard a lot, she was into his boyish nature, but she wanted something more serious. She was ready to settle down. That's why after getting close on the set of Playing for Keeps back in 2011, their relationship soon fizzled out.
"[He] still thinks he missed out. He just wasn't man enough to admit the feelings he had for her at the time."
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