Name that Drama

I watched this drama and can't recall its name. I remember how it started, it showed the main characters when they were in high school. Anyways the male lead's mother was a housekeeper for a family and the mom was treated badly. The son hated this and new the family's daughter liked him so he told her if she wanted to run away with him. But he only did this to get revenge on her mother. 
I'm sorry if i explained it bad but that's all i can recall, plz help me find this drama

Thank you, did not know it was 50 episodes tho :l