what does it mean when someone says the spark has gone?

Well what it means the way i see it there is no love or passion,you will find out when you fall inlove,when you boyfriend kisses you and you melt in his arms,thats loveand if that does not happen well the spark has gone,let me know if i can help any more lots of hugs.

When someone says that, it generally tells me that the lust is gone - the passion. Which can happen to those in love and not in love. But for those truly in love - the "spark" or passion can be brought back if they want it. But for those who it was just lust and never about love - once the "spark" or passion is gone - there is no relationship left. It means it was all probably based on attraction and excitement.