I’m so glad you wrote. Yes, you are right that this could lead to serious trouble. It already is very troublesome.
Children who have been traumatized often act out the trauma as a way to try to understand and master their feelings. It’s possible you have been re-enacting the treatment by your “dad” and/or that you are reacting to the bullying by older boys by wanting to have power over younger boys. I don’t have enough information to go beyond those very preliminary guesses.
But I do know this. The more you masturbate to pictures of young boys, the more you are reinforcing the very behavior you say you want to stop. Orgasm is a powerful, powerful reinforcer. Every time you climax while looking at those pictures, you are conditioning yourself to do it more.
There is nothing wrong with masturbation. There is something very wrong with doing it while looking at pictures of little boys.
Your report that you are masturbating 3 – 4 times a day suggests to me that you are also using it as a way to relieve intense anxiety. It works, I’m sure. Orgasm is an effective stress reliever. However, the more you do it, the more addictive it will be.
Please consider getting into therapy. A therapist won’t judge you. Instead, a therapist will help you deal with your history and learn to express your sexuality in ways that are appropriate and pleasurable. You will also learn alternative ways to relieve stress and anxiety. Do look for a therapist who has expertise in working with young men with high functioning autism.
I wish you well.