Some people get a kick out of the chase. As soon as they feel they have "caught" you, they lose interest and look for their next prey. I've been there and done that. Forget him. If you're friends on Fetlife or any other social networking sites, block him. Delete any emails or messages you've received, delete his contact, any pictures, basically everything. Empty your recycle bin and get to forgetting you ever met him. As NYC said, distract yourself. The sooner you stop thinking about him, the better. Good luck.
Me - Mostly mono female, 39 yrs old, married to Leo.
Leo - Poly bi-sexual male, 37 years old. Married to me and looking.