A source said, "Catherine has told those closest to her that Dominic has admitted having feelings for Lily."
"At first it seemed as though the whole thing was just a one-off but Catherine has since said it's become obvious it was more than that. Catherine feels crushed by it, naturally. It's a huge thing to be coming to terms with," the insider added. "She has since told the people closest to her their marriage is as good as over now and she doesn't think there is a way past this."
The costars were caught getting cozy in Italy in October. West's wife, Catherine FitzGerald, was said to have been "devastated" when the images of her husband kissing another woman emerged.
Last month, the couple put on a shocking display as they staged a photoshoot to tell the world that all was good in their camp. The pair handed out notes to the press that read, "Our marriage is strong and we’re very much still together. Thank you." However, a source told OK! that FitzGerald was actually embarrassed about the ordeal.
"This is a classic case of damage control," the source said. "Catherine agreed to play the game with Dominic and come out with smiles on their faces, even though she has every right to be slapping him with divorce papers right now. But there’s no denying that she’s humiliated by his behavior," the insider said.
Insiders told The Sun that FitzGerald flew home to County Limerick, Ireland, to make up her mind about her future with West with her sisters, Honor and Nesta.
"Nesta has told friends that it felt like a family crisis meeting," a family friend told the outlet, and FitzGerald has been "thinking everything over" after the cheating scandal came to light. "Both she and Honor are fiercely protective of their older sister and want only what’s best for her, even if that means Catherine walking away."
"This is her home, her favorite place in the world and she feels safe here. It’s natural that she’d come home to her mother. It must be hell what she’s going through," another source said. "She is absolutely devastated at those pictures and their story will inevitably have a sad ending."
West and FitzGerald tied the knot in 2010 after they reunited following their college romance. They have four children together: Dora, 13, Senan, 12, Francis, 11 and Christabel, 7. The Tomb Raider actor also has a 21-year-old daughter, Martha, with ex-girlfriend Polly Astor.