You might have realized this in your own life, that one day something or someone can be the biggest joy and love of your heart. But the next day your love is a little less and then you look for something else to make you feel that joy. I've experienced this type of cycle before but with other things its like my heart clings to and is sticky to them. These are things and people I care for and trust, who give me happiness and comfort, who I want to spend all my time with. All these experiences can make my heart feel confused.
But! There is one who I know who is able to fill that eternity within my heart. God created us with eternity because He is the only one who could ever fill it. Its wonderful to know that God didn't just make our hearts so we could fill it with tempory things but made it so we could have the eternal one Himself in us. This is the ultimate satisfaction of our hearts.
I'd have to admit this isn't always my experience but it does give me hope. Each day I want to make it my prayer that my heart is open and soft to the Lord. That each moment the Lord would infuse and saturate me more until He fully gains my heart.