To The Moon and Back- The ML has always been mistreated by his father. But then meets FL and he starts to find happiness again. It's a really cute drama.
Cinderellas Sister- It practically says it in the title. This one wasn't my absolute favorite, it came off as a little slow, but you might enjoy it since you are looking for the "Cinderella" genre. :)
Doctors- FL had a tough childhood, was mistreated, and even blamed for something she didn't do. She pushes through and the ML gives her comfort, and helped shaped her into the person she became.
Go Ahead- This one kind of falls into this category. The ML gets treated horribly by his mother, the mother is basically harboring him for herself. It's quite sad actually. But then he finally gets to move out and go back to his "sister" (she's not his biological sister, they just grew up together) that he's been in love with for years. She helps him heal from his scars and past memories, and they are so adorable. I 1000/10 recommend if you haven't seen this one.
The K2- This one is definitely more on the thriller side than the romance side, but the FL was treated horribly by her family, and the ML basically saves her from all that. This one isn't the most entertaining to me, but some people loooove it. ;)
When the Camellia Blooms- This one fits into your title but doesn't at the same time. It wasn't the FLs family that treated her wrong but the FL was mistreated by her ex-boyfriends family. ( I thinkkkk? It's been a while sorry. ? ) and the people in her neighborhood treat her like absolute crap. But then enters the ML. He falls for her at first sight, and defends her whenever she needs. It's really cute,