These characters have both been putting the work in.
I’d be looking for a serpent at his partner’s ear, planting poisonous suggestions that she deserves more of the company they started equally. If this were real.
That's the problem, the story is saying he stopped focusing full-time on the business in order to make his own ends meet. It looks like the main innovation of the mediator generated deal is that it attempts to reconcile by drafting a way back in to 50/50 if he recommits. The starting 60/40 split is not that important.
This is certainly an example of what I would expect from a product designed to optimize a prenup. You know, they say money ruins people, but sometimes you just have to acknowledge there was nothing really ever there decent to begin with.