Long-term
She was talented when you married: driven, advancing, on a clear trajectory. A few years in, she took a step back at work. A less demanding role. Longer stretches between promotions. Opportunities she didn't pursue. You thought it was burnout, or a lifestyle shift, or a choice to be present for the kids.
It may also have been a financial calculation.
The game
In most jurisdictions, alimony is tied to the earnings gap between spouses at separation. The wider the gap, the larger the payment, the longer it runs. A spouse who believes the marriage is likely to end has a direct financial incentive to manage that gap, not by reducing your earnings but by limiting their own.
She has information about the state of the marriage that you may not have, or may be choosing not to see. If she thinks separation is likely, her optimal career strategy changes. Every promotion she doesn't pursue is a rational response to the incentive structure she's facing.
The equilibrium
This is hard to see because career decisions have a hundred legitimate explanations. Burnout is real. Work-life balance matters. The desire to be present for children is genuine. The financial incentive runs in the same direction as all of these, and is invisible alongside them.
The equilibrium is stable because the strategy is undetectable in real time. By the time the earnings gap is apparent, it's already built into the financial structure of the marriage.
Dominated strategies
Assuming a career slowdown is purely personal is the dominated strategy. It leaves you without information you need.
If you're in a marriage that feels uncertain, understand the financial structure you're in. Not out of paranoia, but because the incentives are real whether or not anyone is consciously acting on them. A spouse who earns significantly less than their potential has a larger claim on your income if the marriage ends. That's the game, whether either of you intended to play it.