"Except for Porneia": Understanding Christ's Most Important Statement on Divorce and Remarriage | Matthew 19:9

Matthew 19:9 is the most important recorded sentence we have from Jesus during His earthly ministry about divorce and remarriage. "And I say to you: whoever divorces his wife, except for sexual immorality, and marries another, commits adultery." Yet godly Christians have differing views of how to interpret this sentence, especially the exception clause, "except for sexual immorality." What exactly does "sexual immorality" (Greek: porneia) refer to here? You can watch this message here.