How to tell your professor that you can't attend class because your getting married
"Professor, I can't attend class because I'm getting married."
Be honest. Not something you want to miss, its your wedding. Your professor will be ok. If you tell them in a decent advance notice they should respect you for it.
If it's a college ... you don't have to tell them anything, really.
Dear *professor*,I regret to inform you that I can't make class today because I am getting marriedSincerely,(your name)