There are plenty of weird and terrible ways to break up with someone. You have experienced one of those weird and terrible ways:
The Sudden And Inexplicable Cold Shoulder
I'm not sure why your boyfriend... well, ex-boyfriend... decided to end a yearlong relationship by cutting off all contact. What I am sure of, though, is that he is selfish, immature and too much of a coward to have an actual conversation.
He knew he wanted to break up with you for a while, and decided the way that hurt him the least was to just go silent. He didn't care about your feelings, only his. I'm willing to bet that how he behaved during this break-up (one-sided and childish) reflected how he behaved during the relationship itself. You've probably had to make a lot of compromises to keep him happy and a lot of excuses about his behavior. Deep down, you probably knew all along that there were things he wasn't giving you - affection, generosity and kindness, to name a few.
As horrible as the break-up was, you're much better off without this man. Hopefully, you never have to date someone like him again.