I think that Cgttown really said it well. Many men don't have a close male friend or group of friends. I have several close guy friends but my best mate is definitely the most important person in my life- besides my wife and kids. We talk about everything and don't hide anything. Workout together, hang out, anything really. We frequently leave each other with an "I love you." It's not sexual, and people who think that it is/ should be, don't understand and probably don't have a close guy friend like that, or maybe never have.
It is really special and I know that it is rare to have that sort of friend.