Sebastian didn't know how to answer that question. because he had no reason to, he had nor reason to not break up with her when he decided to marry Aurora. he had no reason for not breaking his past relationship with Rose even after getting married to her, so what reason is he gonna tell her now? What reason could justify his actions?
this was the first time Sebastian had ever explained himself to a woman. he once never cared what his women thought of him.. and that's the reason why he had many women back then even though he was in a relationship with Rose. and that could possibly be the reason why he had such a hard time with words trying to make things right with his wife.. but anyway, he decided to make everything right.. and he's gonna do just that... if.. of of course he doesn't want his wife to collapse again and suffer from a fever all night again.