Living together vs marriage

Interesting conversation came up this week, which made me wonder has living with a person instead of marriage been a good thing for women??

I'm one of the statistics, that something like one in five marriages end in divorce these days.  Having made my vows once, I have for a long time considered my self of in the camp for people not going up the aisle again. 

This week I got talking to a very elderly lady who couldn't understand living with someone before marriage.  One of the points that came up was sacrifice for the relationship and the sacrifices made are often from the woman in relation to careers and children.  If we are going to have families, the family must come first.  A women will often take maternity leave, she may leave the workforce for a while to raise her children, so she makes a sacrifice to her career for the family unit.  Whilst in this country it is established in law that we receive equal pay for equal work, we are still aware that the glass ceiling still exists.  If women sacrifice more for the family unit then what protection is there in case it all goes wrong.