i used to sleep with a girl like this in college. she refused to let me make her cum, would build up very close and then strongly express all things cease the moment before she orgasms. she was afriad to accept it and feel it. for a long time she even always rejected receiving any oral at all, because it brought her too close to orgasm too easily. she loved giving oral because she diddnt have to worry about that level of intensity happening inside her body, adn felt more in control. she went through all her life having a healthy amount of sex but never experiencing orgasm. i open my mind to the situation and we tried to help her through it for a long time. even when in high spirits, drunk, and perfectly relaxed, she still would instinctively deny herself an orgasm. we were like super close best friends that had sex with each other a lot, never really had any formal relationship structure, but we slept with each over for close to a year. it was at least the tail end of that year before she finally was able to let herself experience that, and she has really learned to embrace her sexuality as a result.
its not difficult to imagine the effects of modern socialization on any person's sex drive, and some people developing a fear of reaching full orgasm, or a fear of completely letting go during sex period.