"They had problems for years, a lot of secret break-ups — but everyone thought that the wedding would make things right.
"In the end it seemed to us like the wedding was like a Band-Aid that was trying to stick over the cracks in the relationship."
The source claimed that the wedding, that was held in Tennessee with Miley's parents, did not reflect both of them and that it was very much on her terms.
The friend believed that the couple "weren't right for each other".
Other friends of the celebrity pair's friend also were "unsurprised" by the couple's shock split, as they'd been "drifting apart" for months.
An insider says the couple still had "a lot of issues" despite appearing to be perfect, telling People magazine: "This split isn't shocking to people who are actually with them every day."
"After they reunited, everyone thought they were this 'perfect' couple, but they still had a lot of issues.
"They're not on the same page when it comes to a lot of fundamental things that make a relationship work. It's not surprising at all."
Another source reportedly told E! News: "They have been trying to make it work for months now but haven't felt they were connecting on the level they were feeling when they got married last year.
"It's been a rough year."
Liam is said to be "focused on a more simplified lifestyle while Miley has been preparing for a new wave of her music career".
The source added: "She has been ready to put out music and be back in the game touring and performing. They really grew apart.
"Miley and Liam have still been communicating and it wasn't a messy split but they have decided they are at different points in their lives currently."