Liberty Ross was reportedly unhappy in her marriage long before husband Rupert Sanders cheated on her with Kristen Stewart.
The model-and-actress filed for divorce from the director six months after pictures were published showing him kissing the Twilight star.
A source told Us Weekly magazine that Liberty, 34, found it difficult to uproot her life in the UK for Hollywood.
"She wasn't very happy, even before all this happened," the source revealed.
"Rupert put a lot of pressure on her to change her life for him and they moved to L.A. for him. She was such a big deal in England - a bigger deal than him even."
Liberty married Rupert back in 2002 and they have a daughter Skyla, seven, and five-year-old son Tennyson together.
She even gave a hint of her unhappiness to You magazine prior to the scandal.
"I went from the glamour of working with Karl Lagerfeld and John Galliano to living on an isolated hilltop, with my husband gone most of the time," she said.
"I romanticised domesticity for a while, and loved having a shopping list of groceries stuck to the fridge for the first time. But moving here and starting a life all over again was a lot harder than I had anticipated."
Despite the upheaval, the couple "did love each other," according to the source, but Liberty's anger over her husband's tryst with Kristen was too much and they mutually decided to split.
"They gave it a shot for the kids, [but] she was just so angry," another insider added. "She's the kind of person who wouldn't really ever get over it."
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