The 48-year-old 'House of Cards' star and Foster have ended their romance after realising their plan to tie the knot wasn't the right decision, reported Us magazine.
The blonde beauty decided to call time on her relationship after spending time away from Foster, 34, filming the hit Netflix series in Baltimore while he worked on a production of 'A Streetcar Named Desire' in London over the summer.
"She got swept up in the engagement last Christmas, but then their schedules got crazy and she realised it wasn't the right decision," a source said.
"The gap just ended up being too much. Ben was kind of immature. She couldn't deal with him anymore," the source added.
The pair met on the set of their movie 'Rampart' in 2011 and are believed to have started dating in February 2012. The actress was first spotted wearing her engagement ring in January this year.