Jessica Simpson is devastated Tony Romo has a new girlfriend.

The 'With You' singer — who was dumped by the American football star in July — can't believe her former beau has moved on so quickly with 22-year-old Candice Crawford, younger sister of Chace Crawford.

A source said: ?She can?t believe it. She doesn?t want Tony back, but no one wants to see that their ex has moved on with a hot, younger girl.

"This couldn?t have come at a worse time for Jessica. It?s opened up a lot of old wounds. She?s pretty insecure about herself."

Candice bears a striking resemblance to 29-year-old Jessica and the blonde beauty is trying to keep herself busy with work to get over her upset.

A friend said: "Jessica is unlucky in love and that's her downfall.

"She's buried herself in work and trying not to focus on the break-up with Tony."

It is also rumoured Jessica has begun seeing ex-boyfriend John Mayer again in a bid to forget about Tony.