This is too sad to be true

I just don't get why'd you'd write such a beautiful love story to then have the mc end up with the horrible monster that k!lled his mother and had no compassion... I don't get it. Maybe as I get older and my frontal lobe develops I become more and more upset at this kind of sickening stories but oh well. I'll enjoy reading about Raonhiljo and the pretty guy for as long as it lasts