secret relationship cohabitating in family home

Where the two leads live together but also one of their families live there too and they have a secret relationship in the house.

I've seen two dramas with this plot, one was korean  where I think the girl pretended to be a cousin or something, and another was a chinese drama which I can't remember :/

Watch "Go Ahead"! It's one of my favorites. Highly recommended! ♡

Glorious Day! I think multiple couples in it actually fit this plot, one of the most underrated family dramas out there imo.