Shin is your ex, and vice versa. You recognize him as a good human being at the beginning and an evil person at the end.

You really hate seeing him kneeling in front of you, his eyes red and sleepy, his face pale, and his body not as big as before.

Shin now regrets it, because of what? Because I was mean to you. Like hurting you, yelling at you, making rough physical touches, and much more.