Some possible reasons why she doesn't want sex........
She doesn’t feel attractive and sexy.
She doesn’t find you attractive and sexy.
She is unhappy with something completely unrelated to sex.
She is depressed.
She has a boyfriend, or she wants one.
She has a girlfriend, or she wants one.
She is selfish and doesn’t care about your needs.
She thinks you use her like a machine, doesn’t feel loved.
She has an untreated medical condition of some kind.
She thinks you don’t love really love her.
She doesn’t like or love you enough to have sex.
She wants some sexy clothes and you won’t buy them for her.
She wants you to buy many other things for her & unit/house.
She wants to feel like a slut and charge you money for sex.
She has a low libido or sex-drive, just not interested in sex.
She gets tired easily and doesn’t feel like sex when tired.
She doesn’t like her job.
She needs a change of some kind to freshen up her life.
She finds her life boring and without excitement.
She likes you but wants to have sex with you and another man at same time.
She likes you but wants to have sex with you and another girl at same time.
Cheers....