Talking to the Sunday People newspaper, the source continued: "He has become increasingly disappointed with the little amount of time he can spend with Perrie.
"Unfortunately she is in a band too, they have so little time together.
"Zayn appreciates how lucky he is, but life is about family for him and he is seeing too little of his loved ones."
Their struggle to fit quality time together into their busy schedules has also meant the couple have not been able to make plans for their nuptials.
He admitted: "We are engaged... I've had a few questions about plans for the marriage; we haven't really had any plans yet."
Despite an imminent ceremony being unlikely, Zayn's bandmates - Harry Styles, Louis Tomlinson, Niall Horan and Liam Payne - have already started planning a pre-wedding celebration, and hope to whisk the handsome hunk off to Las Vegas for a debaucherous stag party.
Niall told OK! magazine: "You know where we're taking you, don't you Zayn ... Vegas!"
Zayn Malik of One Direction. Photo / Getty Images
One Direction's tour manager quits - reports
Meanwhile, One Direction's long-term tour manager has reportedly quit his job and walked away from the pop group's promotional trip in the US.
Paul Higgins, who was reportedly nicknamed the group's babysitter, has worked with the band since they formed in 2010, but editors at Britain's Sunday Mirror newspaper report there has been friction between Higgins and Zayn Malik in recent days.
The article suggests Higgins quit after an argument with Malik and flew back from the US where the boyband is promoting new album Four.
A source tells the publication, "There have been issues behind the scenes for a while and they've finally come to a head leading to Paul's relationship with the band coming to an end. In many ways he has completely run the show while they've been on tour - they even call him Daddy. He became a friend as well as a key part of their management set-up. He's always been at the heart of the One Direction team and it's hard to think of them going on tour without him there."
The news of Higgins' departure comes in the wake of Malik's headline-grabbing absence earlier this week. The singer was missing from the first day of the group's promotional trek in Florida and he flew out later to rejoin them.
His absence was blamed on a stomach bug, but questions were raised during the group's appearance on America's Today show when host Matt Lauer asked whether Malik is dealing substance abuse issues.
Malik denied the allegation.
- Bang! Showbiz, WENN
