When he told me he wouldn't come to Scotland for my wedding last year, I was heartbroken and wrote him an email to tell him so. I've re-read it so many times, and it's not rude or cruel, just sad. I've not heard from him since.
It took a long time to actually realize that K wasn't going to answer my emails, that he really did un-facebook friend me (the horrors!), that he really erased me from his life. I kept thinking he was busy, or sulking. The realization of my expendability was perhaps the most shattering part - that he can go on without me. That I had a different vision of our friendship.
I suppose it is possible to mourn the living. That's all I can do - pretend that K was a friend in a former life. Remember his face every Cinco de Mayo and St. Patrick's Day, giggle at memories, remember the laughs - so many laughs! - and stop wishing.