Heres what I think, and mind you, Ive been known to give bad advice. I too suffer from "foot in mouth". Writing IS much easier for me. Eventually though, you will need to talk to this man face to face. Are you prepared for that?
Second, men too can be shy, someone has to make the first move. You sound genuine in being glad to see him. If you have his address, send the letter saying exactly that, with a suggestion of a future meeting. I'm assuming he is not a Ted Bundy type, but if he is, disregard all I say. There is NOTHING wrong with telling someone you were glad to see them. It makes feel good, or should, and can get the communication rolling. From there, if it's meant to be, it will be. If you do have a history, it's probably safe to give personal contact numbers. I guess I ve read too many books about crazy, deranged sociopaths to say its always safe to do so. Once you have "broken the ice", things will either move ahead naturally, or you will discover that he is already involved, not interested in that way, or whatever. But unless you try, you will never know.

"This too shall pass...."