Why would he refuse to tell you what you did? My guess is that you are not paying him enough attention and this is his way of getting back at you. You didn't DO anything. He knows how to push your buttons and for whatever reasons today decided to do just that.
Let it go, girl. He will eventually tire of the games if you refuse to play. Be breezy when dealing with him. Don't give him the satisfaction of knowing he got to you.
He can't tell you because there is truly nothing to tell.
Hang in there and don't forget to breathe. *hugs* ~ swl
Look not mournfully into the past. It comes not back again. Wisely improve the present. It is thine. Go forth to meet the shadowy future, without fear. {Henry Wadsworth Longfellow}