This translation is confusing words used was as if it's directly translated thru google but... If I'm reading it right. Yeonjin and his wife has a long time plan of distroying the man who took away someone important to them (aka Yeonjin mother, the wife's muse) so they married, had a child, he intends to cause a scandal that will distroy his father biggest achievement and weakness, him, as the heir, and plans to die, divorcing the wife and leaving theie kid with her. It was all the plan until MoonHyuk caught Yeonjin's attention and other characters showed up, but I believe they are still pushing thru that plan. That's why it angers MoonHyuk (?) For sure he doesn't want Yeonjin to die.... 
