Mick Jagger took to Facebook Tuesday (March 18) to express his sorrow over the loss of his girlfriend, fashion designer/stylist/model L'Wren Scott, who died Monday of apparent suicide. Soon after, the Rolling Stones announced that they would be postponing their tour of Australia and New Zealand.

"I am still struggling to understand how my lover and best friend could end her life in this tragic way," Jagger, who had been with Scott for 10 years, wrote.

"We spent many wonderful years together and had made a great life for ourselves. She had great presence and her talent was much admired, not least by me. I have been touched by the tributes that people have paid to her, and also the personal messages of support that I have received," he wrote.

He signed the message, "I will never forget her, Mick."

Scott, born Luann Bambrough, was found around 10 a.m. Monday by her assistant hanged to death by a scarf tied to a doorknob. No note was left behind, but Scott did text her assistant before her death, saying, "Come by."

A medical examiner will determine cause of death.

Scott was a force in the fashion world -- she started off her career as a model at age 18, heading to Paris to seek her fortune. She then broke into styling, working with the likes of Nicole Kidman and Sarah Jessica Parker (and Jagger in Martin Scorsese's concert film "Shine A Light"). In 2006, she cemented her empire by starting her own eponymous fashion line.

This story was updated at on March 18, 2014 at 2:30 pm ET.