not sure on this one but, the first ep of Emergency Couple has flashback to couple secretly getting married but married life doesn't last long, the rest of the drama though has them as ex's who end up at the same job as interns at a hospital and find their way back to each other.
My Secret Hotel, has lead couple having been previously married out of country with no guests or family, but they are ex's now and meet by chance when male lead is getting married again and female lead is wedding planner it's funny and cute and they have to find a way back to each other.
Neither of these really fits for living quietly, most of the time the family finds out and stirs the drama pot