Graham Colton and Kelly Clarkson
RALPH NOTARO/GETTY; DENNIS VAN TINE/LFI
Kelly Clarkson and her boyfriend since July, Oklahoma-born rocker Graham Colton, have broken up, a rep for the pop star's record label confirms to PEOPLE.
"They remain good friends," adds a source. "They were even out together a week or so ago. But she's on the road, and he's in the studio, and there just isn't time to spend together."
In December, PEOPLE reported that the summer romance was still generating heat between the American Idol champ, 23, and her 24-year-old beau, whose Graham Colton Band was the opening act for her Behind These Hazel Eyes Tour.
As both lived in Dallas, "they have that Texas thing in common," said a source close to the couple, who described the musicians as "both very spiritual and mature for their ages" and theirs as "a committed relationship."
As quoted in the German magazine Bravo, Clarkson, who recently toured Europe, reportedly said of Colton: "He will always be one of my best friends. I'm not sad, really, because our relationship made me believe in love again."
She added: "Graham is the coolest guy I've ever been with. Maybe one day we'll get back together – if we don't have to work so much anymore."
Colton and his band previously opened for John Mayer, Maroon 5 and the Dave Matthews Band.
Grammy nominee Clarkson is due to perform at Wednesday's ceremony. Her multiplatinum album, Breakaway, which spawned four Top 10 hits, is up for female pop vocal performance ("Since U Been Gone") and best pop vocal album.