How Tae Oh has he audacity to care about Sun Woo?

He cheated and never apologized, had a daughter with another woman, hit her, threatened to take her son away, moved back stalked her, hired a maniac to almost kill her, took her son away, almost made her lose her job, he just couldn't see her happy. She can't be without him or with him, made her suffer, slept with her saying he wants everything how it was, and after all that, he cares about her?

He is so toxic, and narcissistic. If he can't be happy no one around him can.