When gorgeous Jessica Simpson tried to do something about Tony Romo‘s cold feet, he gave her the boot – shattering their 20-month romance.

The Dallas Cowboys quarterback coldheartedly dumped the blonde beauty on July 9, the night before her 29th birthday, after months of mounting tension over their clashing lifestyles and Tony’s refusal to set a wedding date.

“Tony pulled the plug because he couldn’t stand the constant heat Jessica was putting on him to get married,” divulged an insider.

“The final nail in the coffin was an argument they had over how to celebrate Jessica’s birthday.

“She wanted a splashy Ken & Barbie-themed bash with all of her celebrity friends, and Tony wanted a quiet, low-key dinner for just the two of them.

“When Jessica pushed, Tony blew up and shouted, ‘I hate this stupid stuff and your whole fake Hollywood life!’

“Tony told Jessica that he wanted to take a break. He’s worn out from bickering, and he wants to concentrate on training for the football season.”

After Tony called his “timeout,” Jessica sent an e-mail to friends, informing them her planned party was canceled because of electrical problems at her parents’ home. “

But the truth is that Jessica was too embarrassed to face friends and answer the inevitable questions about why Tony wasn’t part of the festivities,” confided the insider.