Salaam Alikum, since he had photos, he will try and exploit anytime.
Best thing, Allah knows your intentions are sincere, divulge it to your parents and go to authorities.
May Allah SubhanhuwaTaala grant you help with this taubat an naseeha!
Truth never hurts, always helps over success!
He won't understand your needs as he puts his first totally before yours. It is pointless in explaining anything to him, because likely, he won't listen.
What you can do is be repulsive, vulgar and unattractive, be overly talkative and boring. Be unladylike and disgusting in all manners, dress, behaviour, etc. Behave like a different person that you yourself ...