She found out that her ex-boyfriend was Harry's adoptive brother.

Harry said that his brother was a good, 

obedient,

and fantastic child and nothing like Fleur described

him to be. 

"You don't believe me?"

She confronted him.

"Well you really don't have any proof!" 

He almost yelled at her. 

"You know what? I don't need you!"

She told a complete lie. 

"Yeah fine leave."

He commanded her.

She left and she didn't feel strong, she felt weak. 

She needed Harry and everyone knew that.