In his book The Pleasures of God, John Piper shares why God's love is superior to any love we will find here on earth:

Sometimes we joke and say about marriage, "The honeymoon is over." But that's because we are finite. We can't sustain a honeymoon level of intensity and affection. We can't foresee the irritations that come with long-term familiarity. We can't stay as fit and handsome as we were then. We can't come up with enough new things to keep the relationship that fresh. But God says his joy over his people is like a bridegroom over a bride. He is talking about honeymoon intensity and honeymoon pleasures and honeymoon energy and excitement and enthusiasm and enjoyment. He is trying to get into our hearts what he means when he says he rejoices over us with all his heart.

And add to this, that with God the honeymoon never ends. He is infinite in power and wisdom and creativity and love. And so he has no trouble sustaining a honeymoon level of intensity; he can foresee all the future quirks of our personality and has decided he will keep what's good for us and change what isn't; he will always be as handsome as he ever was, and will see to it that we get more and more beautiful forever; and he infinitely creative to think of new things to do together so that there will be no boredom for the next trillion ages of millenniums.