James M. Cain said this quote

I knew then what I had done. I had killed a man. I had killed a man to get a woman. I had put myself in her power, so there was one person in the world that could point a a finger at me, and I would have to die. I had done all that for her, and I never want to see her again as long as I lived. That’s all it takes, one drop of fear, to curdle love into hate.