"The irony of commitment is that it's deeply liberating - in work, in play, in love. The act frees you from the tyranny of your internal critic, from the fear that likes to dress itself up and parade around as rational hesitation. To commit is to remove your head as the barrier of your life."
Commitment, covenant... these are powerful things and they, counterintuitively, set us free in a multitude of ways.
Note the connection between Ms. Morris quote and John Piper's thoughts on the power of covenant love in a marriage (from "This Momentary Marriage").
"The first way to be shame-free is to be perfect; the second way to be shame-free is based on the gracious nature of covenant love. In the first case, there is no shame because we're flawless. In the second case, there is no shame because covenant love covers over a multitude of flaws (1 Peter 4:8; 1 Cor. 13:6)"..."Marriage was designed from the beginning to display the new covenant between Christ and the church. We have seen this in Ephesians 5:31-32. The very essence of this new covenant is that Christ passes over the sins of the bride. His bride is free from shame not because she is perfect, but because she has no fear that her lover will condemn her or shame her because of her sin."..."Why then the shame [Adam and Eve's shame, after the fall]? Because the foundation of covenant keeping love collapsed. And with it the sweet, all-trusting security of marriage disappeared forever."
If you are married and the "thrill is gone" maybe there is no shame-free intimacy in your marriage. After all your talk of commitment, maybe you have not yet made a covenant to not abandon your spouse physically or emotionally no matter what may come. That commitment is a doorway to liberating "one-ness" - naked and unashamed.