You were in a hidden relationship with Hyunjin, and why hidden? You had a fiancé, he was very toxic to you and used violence against you.

Today was the wedding day, but you ran away from the altar, ran in front of the church and got into the car and the driver was Hyunjin.

Hyunjin: "We will finally be free from him."

He started the car and you both drive to his apartment where all your things were already there.