Dale Earnhardt Jr. just got REAL candid about his relationship with his wife -- admitting they were crashing and burning in a big way ... until they started going to couples therapy.
"Every day was like grinding gears,” Earnhardt said about his relationship with Amy Reimann ... "Just a lot of tension and disagreement and misunderstanding."
Dale and Amy started dating back in 2009 -- and got married in 2016 -- but it wasn't always sunshine and rainbows.
"There were great times -- and then there were days when we would both sort of withdraw and get frustrated with each other and not communicate and hold grudges and, 'I'm gonna show you!