the principle of progress

"In his marriage, he now realised, the principle of progress was always at work, in the acquiring of houses, possessions, cars, the drive towards higher social status, more travel, a wider circle of friends, even the production of children felt like an obligatory calling-point on the mad journey; and it was inevitable, he now saw, that once there were no more things to add on or improve on, no more goals to achieve or stages to pass through, the journey would seem to have run its course, and he and his wife would be beset by a great sense of futility and by the feeling of some malady, which was really only the feeling of stillness after a life of too much motion, such as sailors experience when they walk on dry land after too long at sea, but which to both of them signified that they were no longer in love."

—Rachel Cusk, Outline