Never had a orgasm

Y'all I have never had an orgasm. I get mild sensation from messing with my clit really fast or with a vibrator and my body tenses up but that's all that happens and then it goes away. I literally can't feel anything inside except pressure. I've never been turned on or aroused. G spot doesn't work. Nibbles, licking, sucking, hot breath, or anything else he can do to me has done nothing. My nipples will erect and my vagina will get wet but I can't feel anything, not even on my nipples. I was also sexually abused as a child by my brother. Has any one ever had this problem? What's your story? What helped you? What did you do? Tips, tricks, advice?