That means the nut to remove the fan must be in front of the fan itself. No biggie.
The whole goal is to stop the fan pulley from spinning. You could also do a couple of things: you could take the old belt (if you replaced it) and cut it to where it is just a long strip. Take that strip and wrap it (once again in a clockwise manner) around the fan pulley. After the belt is wrapped around the pulley, you should have a tail from the belt on the top side of the pulley trailing toward the driver side. Take your combo wrench and apply tension counter clockwise, all while applying tension to the cut belt. The belt will cinch up a little bit, and once it has stopped, try to break the bolts free.
The fan and the fan clutch shaft will turn freely, so no matter how much pressure or how you grab it, it will still turn. If you have air tools, that is a good way to help bust a tight bolt loose.
I learned the belt trick from poverty...lol