Falling In and Out of Love
Remember how easy it was to think of ways to be kind or generous to your husband or wife back when you were dating? Remember how you ate that stuff up when he or she did things for you? Remember how you could do something nice without expectations and still be surprised and delighted when something nice happened in return?
What stops you from doing those things and enjoying those benefits today? Perhaps you haven't fallen out of love, only out of the habit.