MY tells Lee Gun that he doesn't have to comยิ้ม anymore, he can forget everything, she will remember Keddong.
LG says why shall he forget? MY says cuz it is HER child. He gave up every right to the child (reminiscence of document Sera gave her, and his word that he gives up right to the child)
LG points out that it's HER who decided to move on, changing name and all. MY says new start or not she will never forget Keddong, altho he prob could forget. They basically were hurting each other, telling each other to forget.
MY leaves, LG sits there and eats the cake he bought for Keddong, saying "Keddong-ah, father is sorry again today.