Zayn Malik spoke to each member of One Direction personally before quitting the band.
The 22-year-old star, who announced he was leaving the group earlier today (25.03.15), reportedly wants to get "away from all the craziness" of fame because he "just wasn't happy."
A source said: "He felt he had gotten everything he can out of being in the band and that it was now time to change his life and be away from all the craziness."
The British singer's bandmates, Niall Horan, Liam Payne, Harry Styles and Louis Tomlinson, weren't surprised when he broke the news to them on Monday morning (24.03.15), as they "knew it was coming" after he left their 'On the Road Again' world tour last week due to stress and rushed back to the UK to be with fiancée Perrie Edwards after he was photographed holding hands with student Lauren Richardson in Thailand.
The insider told UsMagazine.com: "Zayn announced his decision yesterday morning. He apologised for putting everyone in this situation and he spoke to each band member personally. Everyone will miss him."
Another source said the star has had a "very hard time adjusting to this level of fame" since joining the group during 'The X Factor' auditions in 2010.
The friend added: "He was always the more shy and introspective one. The stress got to him and he just realised he wanted a normal life. It just got to be too much."