Orgasm happens primarily in the brain.
"Sex" with a partner does nothhing different to the body than masturbation can do, save create pregnancy or spread disease. So, no: there aren't some women who, physically, can only orgasm with a partner.
But again, orgasm happens primarily in the brain, so some people may only feel mentally aroused with a partner, or alone, or with any number of particulars. However, if someone feels total zip alone, they're pretty unlikely to have mind-blowing sex with someone else. May just be you're not at that point in your development to feel strong arousal.
Per your last question, not really. In utero, the penis and the vulva both develop in such a way that your clitoris is basically where your external genitals develop outward from. There are plenty of anomolies of all types in humans, so it's not impossible, but it'd be seriously unlikely. There are also some genital variances that can happen with intersexed individuals and others, but again, that's rare. If in doubt, just ask your gynecologist to take a look and point it out for you.
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