Her change.

Bree drew in a breath as she looked at Yakov, he wanted to believe that he was just lying to her, was trying to say sweet words to make her lay her guard down but she couldn't do it. Not when he was looking at her with that serious expression of his without any twinkle in his eyes or any teasing glint in them. His voice reeked off nothing but sincerity and Bree couldn't help but suck in a shaky breath as she took his hand in hers. 

A subtle zap went through between them as soon as she touched his hand but Bree ignored it as she ignored the hungry and possessive gaze with which Yakov was looking at her, because she knew he wasn't looking at her but the shell she was occupying and honestly, she has never been a fan of love that started with physical intimacy. She was romantic and believed more in heart-to-heart conversation and laying their walls down before walking to that stage where she was willing to share her body with anyone.