What's the story between Susan and Li Mei in Happy Old House? Who can say it completely?

Susan's father and Li Mei's father are old enemies in the shopping mall. Fu Su used some means to bankrupt Li Fu, and Li Fu died. Susan fell in love with Li Mei and broke up with her father in order to be with Li Mei. After Susan and Li Mei were together, Susan was often chased by Li Fu's former men, and Li Mei's men no longer admitted that Li Mei was a member of the Li family, so Susan and Li Mei lived a very poor life. The child they gave birth to got pneumonia, and the family had no money to treat it. When Li Mei went out, Susan went to Sue's father with her child in her arms. Sue's condition for treating the child is that Susan should leave Shanghai at once and not inform Li Mei. Later, when the child was cured, Su Zhong (the servant of the Su family) sent him to an orphanage. Li Mei, who went out to find money, went home, but she couldn't see Susan and the children, so she went to Sue's house. No one in the Su family paid attention to her. She thought Susan had cheated her, and soon she went crazy and died.