Traditionally, it has been the man that has been the main bread winner for the family. When it came time to divorce, it was the man that paid spousal support; and when a prenuptial agreement was negotiated, it was to protect the assets of the husband. This isn't necessarily the case anymore for New York couples.
With many couples marrying later in life, the possibility of the woman being the main bread winner in the family increases. Women are starting their careers before getting married and acquiring their own wealth and assets in the process. As with any man that has done the same, a woman may need to protect herself just in case the couple gets divorced.
Keeping premarital assets separate is a good idea for any woman. This could include monies earned or inherited prior to marriage. It never hurts to keep a separate account in order to avoid commingling all of the couple's assets.
It may actually be easier for a woman that earns more than her husband to maintain some independence during the marriage just in case it falls apart. It could also remove the financial barrier that often exists in a domestic violence situation. Many women that suffer spousal abuse feel they are not financially able to leave their spouse.
Now that couples in New York are more accepting of prenuptial agreements, there isn't any reason not to have one. The stigma that having such an agreement is "planning for divorce" is quickly fading in today's society. As such, women have just as much right as men to ask their soon-to-be spouse to sign one.
Source: Forbes, "Divorcing Women: When You Earn More Than Your Husband," Jeff Landers, April 10, 2013