My good friend Travis McSherley, the editor of (a ministry of Prison Fellowship), wrote a good article contrasting happiness and joy in the context of marriage. Says Travis,

…Happiness and joy are not really the same, though they are clearly linked. In many ways, happiness is the world’s cheap imitation of joy, perhaps the way lust is a lesser substitution of romantic love. Happiness is temporal and physical; joy is eternal. Happiness is primarily a feeling; joy is primarily a choice. Happiness is easy, since it requires the absence of pain; joy is often quite difficult, coming in spite of pain. Happiness is self-centered; joy is others-centered and God-centered. Happiness is surface level; joy is soul level.

To set a marriage relationship—or any relationship—upon a foundation of happiness is to build on a most unsteady surface indeed. When the inevitable rains and floods come, the edifice is destined to collapse, likely crushing the people inside.

You can find the whole article here.