I generally like what Lauren has to say but, in this particular case, I think that she's missing a few key points.
1) Most men, even if they are making incrementally more than women -- a reality that hopefully will diminish over time -- are not planning on their retirement with great intelligence either.
2) For the lower and middle-class, it has always been "easier" for couples to survive financially compared to being single, particularly if children are involved.
3) Most jobs are not designed to enable employees to retire at any time, whether you're a man or a woman.
The issue is not getting married; the issue is being financially literate from one's early twenties rather than in one's mid-forties and then learning to act in one's own best interest.