Married Couple with TN domicile considering purchasing a home in DE but are trying to determine resident/non-resident status and required reported income in DE.

Good Evening,

My wife and I live in Tennessee currently and own a home here.  I am an airline pilot that flys out of Tennessee and my wife is a stay-at-home mom.  We are considering purchasing a second home in Delaware where my wife and kids will spend a majority of their time at.  I will continue commuting between work in Tennessee and the family in Delaware.  More than likely, I will not be in Delaware for more than 183 days out of the year, thus qualifying me as a non-resident according to Delaware here (https://revenuefiles.delaware.gov/2018/TY18_booklet_nr.pdf).  Federally, my wife and I typically file "Married, Filing Jointly".  On page 9 of the above referenced document, it mentions that "You may file joint or separate Delaware returns." It also mentions on page 1 "Non-Residents – File a tax return if you have any gross income during the tax year from sources in Delaware".

If my wife has no income from Delaware or anywhere else, and I qualify as a non-resident (having income from Tennessee as a pilot) do we even need to file at all in Delaware?