A blende family coming together. As their, respective, parents find love again with each other and get married, their children learn how to live and grow to love each other as one family and not two.
THE PARENTS:
Both of the shows have a similar background story for the parents, as both fathers lost their wives and both mothers got a divorce.
THE CHILDREN:
The shows, introduce us to how the children get affected and how they come to accept their new siblings, as well as their own personal growth. In ways that you can connect with the children and follow their journey

FML's both pretend to be their brothers and fall in love with their brothers' band member.
Both involve the music industry specifically bands

FML was also fat and goes under a transformation, to change all her misfortune and still win the MLs attention.

both leads from each drama ends up living together and have a housemaid/assistant relationship.
krDrama male lead is an extreme germophobic and can't seem to keep housemaids as they don't clean to his standards, having meet the female lead they end up in a contract to clean his home however the male lead doesn't know about the actual contract.
Cdrama male lead is also clueless about the actual meaning behind their contract

both deal with ghost, however this is about a detective and a woman who does anything in her power to not see any ghosts

both are contract marriages
HOWEVER, this marriage is based on finding a new mother for his daughter before...
also shows the relationship between his daughter and new wife develops overtime