Saying "I love you" and showing the love for someone is two different things. And yes, you have to show how much love you have before and how much love you have for that someone in your life.
Proof of love doesn't end. You need to keep proving your love till your last breathe. Rumours about your partner, financial constraints, sickness, intolerable in-laws and rift such peeps can bring between you and your partner (or other loved ones), barren-ness,impotence, etc. These are tough times that test the love you claim to have for someone. How strong will you remain? Can your love conquer? Can your love withstand all these fire? You need to keep proving. That's one truth