Birken have you thought about contacting National Ugly Mugs and speaking with them for support as you we're forced into prostitution which is sick and maybe NUM could contact police for you? As both the man who got you into it and punters taking advantage are guilty.
To do with your pictures i hate to say it but even if he agreed to delete them etc chances are he will keep a copy.
He sounds like a pervert scumbag as knew you was pushed into having sex with men at just 18 years of age but comfortable with it.