"Why can't you come? I've alredy prepared much for the three of us. Can't you just have dinner here?" Zella felt awkward after seeing Tina talking to her daughter. The first thought she had with their conversations were sophisticated, as well as having a good impression with the strangers witnessing the scene.
Zella hasn't known if her family exists, or even a single person that is her relative, except from her husband. She didn't even know if he was real. Zella should have known how to keep the distance apart. If she has short-term memory lapses, then that wouldn't be a big problem.
If she continued to pretend losing it every day, she wouldn't have to fall in love with Leo if she never needed it. But no matter how she resist, it still happened. The days overpass, and her missing heart quickly grow alone, like no one can ever bring it back alive.