Your fiancé probably doesn't have the first clue in what goes into a wedding.
Get your wedding planner, write it all down, and show him. Once he gets over the shock, you'll both probably be able to identify areas that interest him. Make lists of the things you've each agreed to do, and cross them off as they get done. At the very least, he'll be far more supportive when he sees what you're going through.
Treat your fiancé as a bit of a pinch hitter. Sure, you may be fully aware that you can shave 5K off your costs by starting your favor crafts and reservations 18 months ahead of time. But if he's like most guys, the wedding won't become real to him until it draws closer. Expect him to jump in about six months before the actual ceremony, and break into a (relative) frenzy of activity about one month in advance.