A poem about social indifference that isn't from someone famous

There's a moment in every relationship that is about to end in which you just know that, no matter what you do, there's no going back. No matter the causes, you know the imminent moment has arrived. You still have feelings for this person, but you can't see a future with them anymore. As in Lowell's poem, all those joys have become just a habit. They no longer seem as real as they used to be.

"A Fixed Idea" by Amy Lowell