When friendships end

It didn't occur to me how often this has happened in my life until the other day when I started thinking about it. Friendships end often due to fights, and I have had my share of those, but there is another kind that really bugs the shit out of me. I hate it when you lose a friend and you have no idea why. You can sit there and guess at possible reasons, but it is the not knowing that makes it hard to move on. I have had my fair share of drama, and due to that drama, things change, and realtionships end, and I can accept it. I often think about these people, wonder how they are doing, think about how close we were at some point in our lives, and what a pity that we no longer speak. The ones that really make me angry though is the ones that just ended cold turkey. I had one such friend. He was like a brother to me, we were inseparable when we lived in the same country. People even thought there was something more going on between us, but nothing ever did. Did he have more than "friendly" feelings towards me, possibly, but he never said anything. I loved him like a brother. Long story short, I moved countries, he moved countries, we slowly spoke/emailed/messaged less and less. I got a life which he was not a part of , he got a life which I was not a part of. I forgot to mention that he was married and had kids even through the early parts of our friendship. After visiting me, something went wrong, we didn't have the best time, we bickered, but I thought that was normal. We used to bicker all the time. He was cold after that visit, he was clearly angry about something, but didn't share. He wasn't very good at talking about his feelings. I got sick and tired of the way he was treating me and his immaturity for not addressing the problem. He left it there, I left it there. We didn't speak again. He sent me a message about 10 months ago congratulating me on the baby, I never replied. I had no idea what to say. Am I sad?Not really. Most of the time I don't really think about it, but to me the person I used to know was someone else. The person who he has become, is someone I don't know, so in a way I lost someone and that makes me sad. We used to laugh a lot, we knew things about one another that no one else did, we used to have the best time together doing very little. He was my best friend. I wish him all the best in life, but will forever be offended at how he treated our friendship, and how he decided to end it.