Past abuse preventing orgasm?

I have never been able to have an orgasm from penetration during sex. I get really close but never reach climax. I always feel like something is stopping me. Like I can't let go and let it happen and I can't help but wonder if it's a result of the sexual abuse I've had in my past. I was sexually abused at 15, 16 and 19. I never talk about it. Thoughts?