Rachel dumps moody Robbie

He's been linked to some of the most glamorous women in showbiz, but today yet another of Robbie Williams's relationships is said to have hit the rocks.

Rachel Hunter is reported to have ditched the mercurial singer, frustrated with his violent mood swings.

Friends say Rod Stewart's estranged wife could no longer put up with Williams's intensity and emotional demands. "He is constantly fighting his own demons," said one. "It makes him a difficult person to be close to and Rachel couldn't cope with it any more."

The couple appeared to enjoy a strong relationship since getting together nine months ago. Williams based himself in Los Angeles so he could be close to model Hunter, who lives with her children Renee, nine, and Liam, seven.

While her home was being refurbished she stayed at Williams' £5 million mansion, but the friend said the couple had run into "a rough patch" since Christmas, with Williams in the Far East promoting his album, Escapology.

"He found it difficult being away from Rachel for long periods of time and hated them being apart. The relationship started going downhill and Rachel just decided she wanted a clean break."

Hunter, 33, is understood to have told Williams it was over on the eve of his 29th birthday, today. The friend told the Sun newspaper: "Rachel is a strong independent person and she feels she hasn't got room in her life at the moment for someone who is so needy and whose emotions are constantly swinging."

The friend added: "She thought they were a perfect match because they had so many things in common. Maybe if Robbie can sort his head out she will have him back. But at the moment it has all fizzled out."

For Williams, who is thought to be on anti-depressants, this is yet another low point in his rocky love life. He was engaged to All Saints singer Nicole Appleton, but they split in December 1998. Corr's singer Andrea Corr dropped him after a few dates in 1999 and constant rows ended a four-month relationship with Big Breakfast host Tania Strecker. In 2000 he began seeing Geri Halliwell but later called her a "demonic little girl". He has also been linked to Anna Friel, Joely Richardson, Denise Van Outen and Tara Palmer-Tomkinson.

Today Williams is understood to be alone in LA. "There's no animosity," said the friend. "It's just sad for them both."

News of his split with Hunter came after she was photographed apparently flirting with a male friend while filming a new US television series - though one of her friends insisted there was "nothing going on".