Their decision comes eight months after the tragic loss of their newborn son, who died shortly after he was born.
Corrie producers confirmed the split, saying: "Jamie has moved out of Kym's house in Cheshire. There is no one else involved and neither party wish to comment at this time."
Kym and former Hollyoaks actor Jamie first met on a train to a London award ceremony in 2007, but they didn't get together until after Kym's split from her husband, EastEnders star Jack Ryder.
The 33-year-old actress, who has two children from a previous relationship and Jack were granted a divorce in March 2008.
Kym and her new love announced last December they were expecting a child together, but their son Archie Jay died moments after being born 18 weeks early on February 11.
Pals said their relationship began to falter after the heart-breaking news. "They were both devastated," says one. "But they had not been together long so they found it hard to deal with."