Could be a few different things - Maybe she isn't developing any follicles - Have you palpated her? Can you feel any? Maybe she don't like him - Maybe he don't like her...BP's are strange - Once you think you have them figured out they throw you a curve ball...Good luck -
BT
Yes, she has follicles (aka - a string of pearls) when I palpatate her. I'm thinking it's time to let some other males come up to bat!