Both have a slice-of-life sitcom feel about them, and both feature a chaebol living with a family pretending to be middle/working class. I Live in Cheongdam-dong is a proper sitcom and therefore incorporates situational comedy as well as screwball and slapstick, while My Merry Marriage is of course more influenced by the daily drama formula, so it has tragic pasts and family mystery; but both are invested in portraying a light tone, and I wouldn't be surprised if My Merry Marriage were influenced by I Live in Cheongdam-dong.