Filing state tax in 2 states - married filing jointly - only one spouse liable?

My husb is a truck driver and his employer is based in Iowa. We live in Nebraska and file state tax here. He also has to file in Iowa to get back what was paid there since we only have to pay in one state. How do we do this so my income isn't included in the Iowa filing since I never worked there? Does he have to file separately first in Iowa, and then we file jointly in Nebraska? I usually use Turbo Tax. thank you!