"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."
Earlier this week, sources told the Daily Mail that FitzGerald, who has four children with West, has grown tired of being an actor's wife "with all that entails."
"He lives this other life where he's away at least half the year and she and the kids are waiting for him," claimed the source.
Last month photos published in British tabloid The Sun showed James and West getting cosy at the Leonardo da Vinci airport as they headed back to the UK, and Page Six reported they were also spotted making out.
"The pictures of Dominic in Rome show just how separate their lives have become. She's been humiliated. Painful as it is, this looks like it could be the time to leave him," the source told the Daily Mail.
An interview with West recently resurfaced, where The Affair actor discussed cheating.
In the 2016 interview with the Evening Standard he implied women should be more understanding of affairs.
"I think women should be more indulgent of affairs. I really do. It's daft to kick someone out over a fling. Isn't it?"
"Everyone should turn a blind eye to men's behaviour between the ages of 40 and 50. Let it all blow over."
