You are a single mother. You got pregnant by your ex who didn't want to have a kid, so he left. He was perfect, and you guys ended up marrying, becoming a happy family.

Before bed, jaehyun ran up to you in tears

jaehyun: "mama... daddy hit me.."

just before this taesan and jaehyun were sitting on the couch, watching his cartoons and when taesan streched, he accidentally hit jaehyun.