I would imagine if the females are pregnant all the time they will not live as long. As far as I know the females store sperm and will probably get pregnant on there own if they have been kept with a male. There is always the chance some fry will make it. I don't believe Mollys are that aggresive about eating there young.
But all in all I would keep them seperated.
From where the sun now stands, I will fight no more forever.