Why can’t i orgasm when having sex?

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I been having sex for a while and when i’m having sex with a guy i never fucking orgasm. Wth is wrong with me? like i know how one feels thanks to me but when it comes down to having sex with someone it just never happens. Also after y’all orgasm is it normal to not wanna have sex anymore? most people can go round after round but when i’m done with myself i just be done . HELP lmfao