Odds are, you and TOM Arnold have something in common. Neither of you, most likely, was summoned to witness Roseanne's Valentine's Day wedding to her former bodyguard and third husband, Ben Thomas. Had you been so favored, you'd have received an invitation decorated with a pair of hovering cherubs. You'd have read that ""On this day, I will marry my best friend. The one I laugh with, live for and love.'' You'd have known the hitching would be held at Caesars Tahoe Hotel and Casino in Nevada. You'd have been told to use a code phrase (which we're not sharing) when you booked your room. You'd have starved yourself for a week in anticipation of the luncheon reception at the local Planet Hollywood. And you'd have known that dress was casual. Or maybe you'd have guessed that anyway.