If he doesn't feel bad you can't make him. I was with a guy like that once and I spent almost an entire year trying to figure out how he could do that to me and not feel any remorse. Then I realized that I had to find my own closure. The comfort is realizing that at least you can still look yourself in the mirror. You're not the bad person, he is. Life will go on for you and you will be stronger. He will continue to go through life hurting people and having people hate him. Not much of an existence if you ask me. Good luck to you.
Move on with your life. The sooner you do that, the sooner you'll stop worrying about it.
Ignore him. Scorpios hate to be ignored. They love to be the center of your attention & your life.