How to spread peanut butter that is required to stay refrigerated?
The easiest solution that comes to mind would be to figure out how much you need for a sandwich, remove that from the jar, set it on the counter to come to room temp (or put it in the microwave for 10-15 seconds) and then spread it when it's warmed up. 

"Refrigerate after opening" doesn't mean that it must be in the fridge every second, though... so even if you left the entire jar on the counter for 30 minutes to warm up, it shouldn't pose much of a problem.