How can one deal with conflicting feelings of love and hatred towards his future wife, after discovering her past and her relationship with her married professor?

Getting to know one another between young men and women, and love relationships between them, are doors to evil and corruption. Your questioning the girl about her forbidden past and her telling you is impermissible; she should have concealed herself, for repentance erases what came before it. You do not have the right to seek out the aforementioned teacher and punish him. If the girl is righteous and upright now, do not find fault with her. If she is not upright, then leave her and conceal her secret. If you fear the impact of this incident on you, then turn away from her.