a lot of the lone parents/relationships boards have comments from single women who say that they are happier on their own. now, many of them may well have been in unhappy (or worse) relationships, but they are not rushing into finding 'mr right'. also, many of them had this situation 'thrust upon them' by men absconding, so it wasn't a conscious choice.
however, i would say that it is much easier to live like this after having children. not only does the experience (mostly) teach you maturity & self-reliance, but it also removes the drive to hook up with someone just to have children. women in this situation can be more picky, and only have men in their lives how & when they want.
if you compare the stereotype of a bachelor in his 40s to that of a spinster in her 40s, it becomes glaringly obvious how much pressure society puts on women to become a wife & mother. biology also pushes us that way, and often we are left in ok but not great relationships, which make us unhappy because we have to live them every day.
in other ares of our lives, it is possible to deal with this, relations with parents, friends, work colleagues, and the work itself. if it's ok but not great, does not affect us so much. if, however, it's your home that makes you feel like that, it can make someone truly unhappy.
which is reminding of the 'cognitive dissonance' thread from a while back.
so, yes, separatism is v much a feminist issue, as our bodies, our families & society at large conspire to make us live with men, even if it isn't in our best interest to do so.
HOWEVER, the whole issue of children just makes it so much more complicated.