What was their relationship?

Li Lanni pressed her lips to his, unwilling to hear him declare his love for another woman. She loved him. Although she kept backing out every time she was going to tell him this – or other factors kept coming in her way, her feelings were undeniable. 

Ji Xiehan held her waist and stopped the kiss. If he didn't tell her this right now, they might get interrupted again. 

His action snapped her back, making her realize just how childish she was being. So what if she kissed him? If his heart belonged to another woman, there was nothing she could do to make him hers. If she forcefully clung to another woman's man, how different would she be from Li Xiyan, her stepmother who collaborated with her grandmother to forcefully break her parents apart?