After you come out, you realize that a "best friend" is something entirely different.
Not a romantic partner, although you may share boyfriends and hookups.
Not a roommate, although you may live together.
Someone with whom you share a fraternal bond, someone closer than a brother, closer than a lover, who stands beside you as boyfriends and jobs and years pass.
You may mistake the instant connection for passion, and date for awhile, but after a few weeks or a few months, you realize the truth: your connection is on another level altogether.
I know how best friendships end:
1. They require constant contact. When one or the other moves out of town, a daily barrage of letters and emails gradually diminishes to once a week, then once a month, then "it's been a long time -- how you doing?"
When one of you moves in with a partner, the other becomes an ordinary friend, one of several who you call every few days, part of the rotation of guys invited over for dinner every few weeks.
Since coming out, I've had six best friends.
Hell-fer-Sartain, Texas: nobody
West Hollywood: Alan, then Raul
San Francisco: David
New York and Florida: Yuri
All but Viju and David were ex-boyfriends. All but Alan and David were younger than me. All were outgoing, flashy, and uninhibited, drawing me into adventures that I would never consider on my own (I'm always the one in the group who says "I don't think that's a very good idea.").
(Illustrations borrowed from the Hot Guys of Facebook tumblr).
See also: 15 Rules of Gay Cruising.