For whatever reason, he has lost interest in you completely and views you as a non-person for him. He either got what he wanted from the sexting session and doesn't really see a future in continuing to get his jollies from sexting with you.... OR... he feels badly about having sexting with you and is beating himself up over having lost his self-control and is embarrassed by it .... OR... your fantasy is something he found repugnant, and he decided to cut and run rather than continue a relationship with you.
ONE of those is the reason, most likely. My bet is on #1.
Whichever one is the reason, there really isn't a "path back to him" for you. Move on. Keep your sexting to yourself unless and until you know someone well and feel a level of trust that FAR exceeds what you felt with this ding dong.