Spouses living in different states

This is complicated.  My husband and I moved to North Carolina temporarily to support our family while our son was deployed.  Our home is actually in Washington State.  My husband is returning there, but I plan to stay in NC to continue helping out, as our son will be doing some long trainings.  My husband is the primary wage earner.  I am retired, but will be paid a small amount to provide child care to my grandchildren.  How do we file taxes?  Will my husband's income be subject to North Carolina state tax? (We lived together in NC for 8 months.)  We very much appreciate your help.