I wanted to say I thought that was an excellent sort of parable on differentiation. I think the point is that it would be wonderful if two people could go on indefinitely feeling equally "in love" with each other but that rarely happens. However, you can happily be in a very loving relationship in which neither party feels "in love" as long as neither party is seeking to find that feeling elsewhere.
"Tell me, what is it you plan to do with your one wild and precious life?" - Mary Oliver
