Women have been trained to be a timid, subservient partner to men for a millennia, and it's hard to get away from. The answer is the same for women and men: know your value, constantly strive to improve your value, and command that you get paid your value. Also, know your interaction with business is just that, business. Be more willing to cut a business relationship than a personal one. Don't blame yourself if someone doesn't see your value, just find someone who does.
Disclosure: My wife is also a programmer.