So do I force it off or am I going to have to cut it off and get a new nut?
I'd probably try to get some PB Blaster into the exhaust stub threads. Prop up the head so that the liquid might be aided by gravity plus capillary action. Wait a couple hours and try to remove the nut...
gently try to remove the nut.
If she still won't play nice, I might use a propane torch and play some heat on the exhaust nut. Just enough to cause a bit of expansion of the nut but little heat on the exhaust stub.
 Do this outside, Carl. Your bride
really will need the fire extinguisher if smoke fills the house...
wink, wink.When you get the nut off, put it away somewhere safe until you do the anti-seize drill.

Good luck, amigo.