See the bigger map hereAn interesting map of single people in America, and some possible explanations provided by readers:
The reason is obvious....
I travel a lot, and mostly on the East Coast.
All these single women are following me around, looking to part me from my wife....
The other guys are simply left behind (as normal)...;)
and another -highly scientific- explanation, from comments:
Prevailing winds. The prevailing winds blow (very roughly) southwest-to-northeast. Women, being on average slightly lighter than men, tend to be swept further downwind.
This, incidentally, is why the few remaining women in the western and southwestern states tend to be very large. Their lighter, more aerodynamic sisters are long gone.