MLs are both widowers with 3 children and take life too seriously (dictator boomers lol). Both FLs are living an unfortunate life but remain bubbly and optimistic then became nannies to the 3 children.

Same premise. Just when they're about to get married, the girl had a condition that made her lose her memories. The guy took care of her despite her not being able to remember him.

Both have doctor-actress pairings. Both plots involve pretend relationships. Unlike Fluttering Warning though, I find the "villainy" in Love At First Hate to be too petty.