She just chose his life, without even asking him. He was hurt, but his heart wanted to agree to her. He never denied her words but somewhere he also didn't want to listen to her.
He sure agreed to marry Anna in taking revenge against Sara. He can't destroy some innocent one's life in his revenge. But how can he forget her, she was his first and last love of her life.
Didn't she promise him he would always be her? Then why did she ask him to forget her. He will never! Never in this life or next any other can take place in his heart except her. He will fulfill her wish in getting married to another girl but forgetting her and promising he will not end up hurting Anna, no he can't.
He broke down in tears, curling himself into a ball. Why did he feel as if his soul was parted away from his body? It was taken away.