"Weiner-Davis points out that while it’s commonly accepted that couples should make all their important family decisions together, when it comes to sex, who ever has the lower sex drive makes a unilateral choice for them both. And, just to rub salt in the wound, she adds, the disenfranchised, high-desire one is expected to stay monogamous. No wonder, she says, they get cross."
Dear Mumsnetters...this ^^^^^