Is this crazy? There is a guy I spent a weekend with about a year ago...?

...We became completely smitten with each other, and had the most amazing time. I haven't seen him or spoken to him (aside from occasional emails, always initiated by me) in a year. He lives about a thousand miles away, and was completely averse to long-distance relationships. Since then I have dated a few other people, etc. I have since accepted that I'll most likely never see him again. So WHY can't I let go??? I feel like I never got my chance to be with him. HOW can I let go? Help please! I would like to think of something else when I hear sweet/sad songs. I've even thought of asking him to be mean/rude so I can have some real closure!