My MC and IC, after an inciting incident, make a pact to change their lives and throw themselves into the whirl of social ACTIVIY. then they DO it. Then the problem is, as fun and interesting as it is at first it's UNENDING and the reward becomes less rewarding, other things come up, including, but not just, tedium.
So, about a third of the way through the novel, they pretty much stop doing this. There is a lot of other stuff going on during the 15 months of this story,
The point is, their relationship changes. Now, as imperfect organically as this is, I kind of like it a la Sentimental Education because, well, sometimes people stop doing things and go do other things.
The MC is on political campaign in NH for a month for primary season, for example.
However, in other respects, this is by no means the end of the OS Throughline. The Overall Story keeps rolling along.
Here's a fact: over 15 months, relationships can change, radically, in a story or not. It feels artificial and forced to make them NOT change.
Thoughts on how to handle this? I have some of my own, but want to hear yours first.