I’m 26 years old and have never had an orgasm. I don’t enjoy masturbation. When I’m in bed with my partner, he makes me feel REALLY good and just when I think I’m about to come, the feeling suddenly vanishes - it’s almost like I hit a wall and then bounce

My advice is that you start enjoying self-pleasuring. It’s the best way to find out what works for you and to get your body used to having orgasms. Then it will be a lot easier to let him know what you need and to experience orgasms with him. It’s really not fair to expect your guy to figure it out on his own, female genitals are complicated! Two key points as you approach orgasm: 1) make sure you stay relaxed and keep your breathing even. 2) Make sure he keeps his stimulation of you even too, rather than intensifying it as you get more excited, as that causes you to become over-stimulated and lose the feeling, just as you describe. The best orgasms come from subtlety, not intensity.