He's the genuine Chae woo atm. But theory-wise, yes, the play pretend as revenge would happen anytime soon after he hit his head once again (saving Lee Yeon) and comes back to his normal cruel self lol. His "bodyguard" or his bro's spy will reveal Lee Yeon's lie.
In terms of the fckkkn hahahaha there would be many. He would hate himself for how much he enjoys sx w his fake wife that he actually thought he understands how amnesiac Chae Woo loved her wife so much. But he's still mad mad yes as an apologist I still thinks it's the kindest way someone as cruel as him would act (he would be a big bad jerk on those chapters)

He remembers his past already he’s just playing that he doesn’t.….