1 Corinthians 13

Love is patient and kind. Love is not jealous or boastful or proud or rude. It does not demand its own way. It is not irritable, and it keeps no record of being wronged.  It does not rejoice about injustice but rejoices whenever the truth wins out.  Love never gives up, never loses faith, is always hopeful, and endures through every circumstance. … love will last forever!  [1 Corinthians 13:4-7, 8b]

Love will last forever.  How, then, do people “fall out of love”?  The answer is simple.

The fruit of the spirit is love, … [Galatians 5:22-23]

True love is God’s love, His Agape love, and it flows naturally out of relationship with Him.  As long as we maintain our relationship with Him, we will never, we can never, “fall out of love.”