The heroine is neither a bitch nor a fool, nor fights nor snatches her life; the male protagonist has a normal brain and a good body without amnesia... In a nutshell, it is a normal sister who married a girl by agreement, and then somehow changed from "threesome, there must be a lightbulb thief happy" to "the clown is actually me" - the CP I fell in love with eventually became a brother, and the girl I married fell in love with myself...
Purpose: Life is a mysterious thing, don't try to make a deal with it