You know it reminds me of one anime: DNA2. This stupid prince keeps 'nagging' the MC, accusing of plotting coup, but does he realize that his 'nagging' could lead what he afraid to be reality? The MC finally snaps and the only way to get rid of the annoying prince is by getting rid of his royal family.
Yeah, probably it wouldn't go that way and MC just stupidly and conveniently falls in love with him.