Married filing jointly, husband was not in courtry and he will be travelling, but no earnings in USA for 2018

[KarenJ]

He will need to declare his foreign earned income on your joint tax return.  If you are US citizens or green card holders, you must declare your worldwide income every year.

He may be able to use the foreign earned income exclusion and / or the foreign tax credit to offset any double taxation if he had to pay foreign tax on his foreign wages.