She (finally) realizes how bad he was for her. How bad he was to her. He used her. He abused her in ways that left no marks yet left permanent scars. He treated her like shit. He made her feel like shit. Yet, she stayed with him. Sometimes, she convinces herself that he made her stay. But then there are those times where the truth sinks in, where the memory of who she was around him comes back and she cannot deny the obvious. She stayed with him. Not because of fear, or him but because he was the first. He was the first boy who chose her. She didn't stay with him because he loved her. She wasn't that stupid. He only loved himself and his diabolical plans. She stayed because he was living (undying?) proof that she could be loved, that she could be first.
He always managed to bring out the worst and the best in her. She would be pathetic, needy, weak when she was around him. She always let him make all the decisions. She didn't fight hard enough. He was the only one who made her feel. She hated him with more passion than she could muster to love the people who loved her. Also, when she was around him, she was confident, happy, determined. But most importantly, in some bizarre, twisted way, he gave her, her self-esteem back. She started loving herself again. Started expecting respect, love from others. She didn't let anyone push her down anymore, except for him of course. He was the beginning of her new twisted and dark story.
She sees everything now though. She sees that he never bought out the best in her. He couldn't even bring out the best in himself. She sees that he never believed in her. So, how could he have made her believe in herself? He never gave a damn about her. She was the pawn in his endless chess game. She never meant anything to him. Whatever, she is now (confident, strong, independent) is thanks to her, not him, never him. He couldn't even save himself.
She finally understands reality. What they had (what they didn't have) was not any impeccable romance; what they had was a nightmare come to life. She never understood the difference between love, obsession, and infatuation. And maybe, because of that very reason, he got so close to tearing her apart (having her heart). Her obsession with him took away all his flaws and exaggerated his qualities. In her obsessive mind, he became the right guy when really he was the devil. She never loved him; she knows that now. There is a fine line between love, obsession and infatuation. So now, she takes extra caution. Her heart is surrounded by iron, wood, steel, copper, cement walls now. She hopes that the only one, who manages to break them (this time), is the one who makes it all worth it.