She didn't decide to suddenly like it. She decided to make it more bearable and to use it to her advantage. In the end, she was 'on top.' The real change was her finding that she did have power, and learning to wield it, this made him love her instead of regarding her as just another possession. Her later…

How many Starks have to get beheaded before people realize GOT doesn't follow standard redemption character arcs? Just because someone does something good doesn't mean they're not still a piece of shit.