Ayesha, firstly, you are a child emotionally at 13, 14, 15, 16 and way beyond that if you have never been taught what caring behaviour and emotional support should look like. So that wasn't your fault at all.
I'm ashamed to admit, that I was groomed at 30 years old. I met him on a spiritual forum, and he acted like the all knowing, all seeing guru who could lead me out of all my weaknesses. He played on my guilt about abuse, and sold me the idea that if I acted like the strong woman I should be, and stopped hiding behind the innocent child act, men wouldn't abuse me. It made sense, and I wanted to be a strong sensual woman. But his methods were to get me to talk dirty to him over the phone. After I stopped it, and he went very cold and eventually blanked me, I still made every excuse in the book, because I didn't want to admit to myself that I'd been so gullable.
But, talking from my own experience, (it might be very different for you), but sometimes it's easier to blame myself for being an idiot, than to admit to my vulnerabilities and the need to be loved and taken care of by someone that led to me trusting him. The latter brings tears to my eyes, but to beat myself up about it doesn't.