Dating
She seemed like exactly your type. Easy-going, enthusiastic about things you cared about, uncomplicated in ways that felt rare. You took your time and decided she was right for you.
Six months after you committed, you're with someone noticeably different. Opinions she never had are coming out now. The flexibility is gone. Things she said she loved, she doesn't anymore. You feel like you're with a different person.
You thought you were the one choosing. You were the one being chosen for a role that was already cast.
The game
She knows roughly what kind of partner you're looking for. She also knows her actual preferences, limitations, and dealbreakers, which may not match what you want. She has two options: present herself honestly and let you decide, or present the version most likely to secure your commitment and adjust once it's in place.
Honest presentation is risky. You might not choose her. The audition is more reliable. The performance only needs to hold long enough for commitment to make leaving feel costly.
The equilibrium
Once you've committed (told people you're together, built routines, started planning around her), the cost of leaving goes up. She can begin closing the gap between the performance and the reality. Each adjustment is small enough to absorb. The relationship is established enough to survive it.
The equilibrium is stable because the transition happens gradually, and because you've already decided she's worth investing in.
Dominated strategies
Trying to recover the version of her you committed to is the dominated strategy. That version was a performance. It isn't coming back.
The better move is to pay attention before you commit. The audition phase has tells: positions that feel too convenient, enthusiasm that tracks too closely with yours, an absence of preferences where you'd expect them. People have friction. Someone with none is managing their presentation. The time to find out who you're actually choosing is before the role is cast.