In his early life, Liu Bei have two recorded spouses: Lady Gan and Lady Mi.
Lady Gan was both Liu Bei favored woman and Liu Shan biological mother, so it is no surprise that she received great honor granted by both Liu Bei and Liu Shan.
However, Lady Mi is still Liu Bei first wife and the sister of two of Liu Bei's subject, Mi Zhu and Mi Fang. What could have happened to her that she simply disappeared from recorded history?
Shu records were pretty bad, hence the lack of information about their state and officers/administrators. When you add the fact that you are a woman, It's even worse.
I think the little info we have on Lady Mi is already not bad since it seems Liu Bei had other wives whose names are not even recorded, the same can be said for Liu Li and Yong's mothers.