I will say I lied. I want Cathy back.. But if not I want to Cucked by Rusty if he's not Gunna bring her back I want to see her happy. I want Rusty to confide in you about starting a relationship with her.
It could be part of Isabella route maybe as well they're friends they are both dating a student they have plenty to confide in each other. Also with the Soft lock out of Izabella over Cathy it makes sense in the long run if this is where the story is going.
Also, what if the MC is narrating from the past because his son is reading his diary after he passed.
Like he did with his mother. Maybe he followed in her footsteps and started writing he's already a song writer.