I agree, my wife has no 'primal' desire for me at all, as I just don't get the ******* rushing through her veins when it comes to sex. She likes and prefers large dicks (black or white) as apposed to my small one. We still have sex, mainly oral for her, but I occasionally get to give her anal sex, I might get a handjob every now and again, but there is no 'raw/ animalistic passion' like there is when she is with other guys. At best, i'd describe our sex life as 'maintenance' sex.
She is more than happy that sex for me is masturbating, but every now and again, she'll throw me a treat.