Matthew McConaughey's piece of relationship advice that keeps his marriage to Camila Alves strong

Matthew McConaughey is sharing the key to making his marriage work.

During a recent interview with Fox News Digital, the 56-year-old actor spoke about his new film, "The Rivals Of Amziah King," which arrives in theaters on Aug. 14, and the biggest lesson he learned that has contributed to his decades-long marriage.

"You got times where one seems to be affirming and sprinting ahead," he said. "And you got times when somebody else may be a little more insecure or a little more unstable...