I'm pretty sure it was the opposite. Director though that he, the director, would be MC's first experience in love where MC'd break up with. MC is still young, thus he'd consider his love story some more flavour. Or so, that's what the director assume.
It's basically the same thing as he's just expecting them to break up just cause of a silly reason. Idk man but he's gotta get his priorities straight
Sure, but it's not that far fetched from the main story. The director got ditched exactly by the quite similar reason, so it was a valid concern. It'd be more silly, story wise, if they just brushed it just like that. Like, they should do typical SOL yonkomas if they don't want to dig more regarding the lore or characters' depth
This whole side story thing started off bcs the director considers MC as just another boyfriend where he'll eventually Break up and go their ways.
Which kinda feels frustrating cause what was the point of the whole main story to just end up Thinking THIS.