...I'm really sorry to hear about your friend. :( I lost my best friend of 12 years this past summer. We had a strange kind of falling out too. I'm sure jealousy had something to do with it, but it was mostly just bitterness and years of unresolved problems that couldn't be talked out. I understand how much that hurts, that even though you'd give anything to work it out, the other person just... doesn't want a damn thing to do with you. I drank a lot more when I was going through all of that.
Hang in there. Don't pressure yourself into new relationships and friendships. They'll happen eventually and naturally, I bet. I actually only get out to hang out with my friends once a week, sometimes every other week, but we're still cool with each other.
I hope one day you guys can at least be on neutral terms. I don't even like thinking that the other person is bitter or upset because it feels wrong for that to fester without doing something about it. :(