Re: Aisha (R)
Divorcing an interfile wife may be more of a cultural practice than an Islamic one. You are allowed to have up to four wives and a case where the first wife is infertile is a good example of when a man can possibly go for another wife without having to divorce the first one.
The wives of the Prophet Muhammad (SAW) were given the title of 'Mothers of the Believers.' No one else was allowed to marry them after Prophet Muhammad (SAW).