The fact that you are expecting perfection from your woman might be what is killing your sex life.
According to a recent poll,
The study asked the respondents questions about desire, arousal, lubrication, orgasm, satisfaction and pain. They also answered questions about sexual performance standards imposed by themselves on themselves, by themselves on their partners, by their partners on themselves and by society on themselves. They were given a follow-up 12 weeks later.
It was found that partner-prescribed perfectionism was the worst sex move. It is not only associated with lower sexual esteem and higher sexual anxiety, but predicted longitudinal decreases in sexual esteem and increases in sexual anxiety.
As well, partner-prescribed sexual perfectionism is a psychological factor that may contribute to sexual self-concept problems in women.
So, in conclusion, positive reinforcement and encouragement is the best way to get her to open up sexually. Accusing her of being bad in bed, not doing something well, comparing her to an ex or another woman sexually will only cause her to withdraw even more, making her uninterested in sex with you.