“Zayn is exhausted and just needs a break,” the source says. “Out of every one of the boys, he’s the one who struggles dealing with being in the spotlight the most. He can’t cope with the level of scrutiny he gets put under. He’s just 22.”
The band’s rep said in a statement Thursday that Malik had “been signed off with stress and is flying back to the U.K. to recuperate,” just hours after he sat down with his management and the band to tell them of his decision, according to the source, who adds, “He’s going to stay with family in England who are really concerned.”
The breaking point for Malik came on Wednesday when reports surfaced that he was cheating on his fiancée.
“It all stems from photos that hit yesterday of him with a fan which caused huge problems with his girlfriend, Perrie,” the source says. “The media accused him of cheating and he exploded over it. He’s had enough of the constant craziness.”
Malik took to Twitter to defend himself. “I love a girl named Perrie Edwards,” he wrote on Wednesday. “And there’s a lot of jealous f—s in this world I’m sorry for what it looks like.”
Editor’s note: A previous version of this post contained information from an Instagram account purporting to belong to Malik’s younger sister, Safaa. A rep for One Direction confirms to PEOPLE that the account was a fake, and the information has been removed.