The devil's wrath

The damage had been done.

After his actions, she would surely despise him eternally, which was precisely his intention. She was engaged to his younger brother, and betraying his family was not an option. They had provided him with everything: life, status, and identity. Without them, he might have perished in that forest. 

Moreover, he knew that Amelia would be far more happy with a human rather than being with a devil. Cassius was a good man, and he would make her happy. If she married him, she would get everything she deserved. 

With him, she would only get hurt and pain.

He knew he was being selfish. He had sacrificed his own happiness and broken her heart for a twisted sense of duty towards his family. Pain gnawed at his soul as he realized the enormity of his actions.

He had torn Amelia's heart to shreds and betrayed his own family. The guilt and shame were unbearable.