Old Dominion's writing process...
Ryan Hurd and Maren Morris become part of duet history...

Old Dominion knew they had a hit on their hands with “I Was On A Boat That Day” when they noticed fans dancing to it during show. 
The guys recorded their new album over three weeks in Asheville, North Carolina. They'd write a song in the morning and then they'd record it in the afternoon.
“Time, Tequila, and Therapy” is out now.

Ryan Hurd and Maren Morris' duet 'Chasing After You' has become the third to hit the top 10 from a married couple this century, as in since 2001.
Clint Black and Lisa Hartman Black did it back in 1999 with 'When I Say I Do,” and Garth and Trisha dropped three duets together since marrying in 2005. They had some other hits too, but that was pre-marriage.
And technically Blake and Miranda never released a hit duet together, unless you count “Boys Round Here,” but that featured the Pistol Annies. And, well that is not the same.