Because if you divorce her, it's your fault. See also: weaponized incompetence.
The belligerent/immature partner (sadly, not a gender-linked thing; anybody can suck this way) will make The Thing a problem. The Thing can be loading the dishes or communicating about the kids or literally anything they should/could do correctly, and they deliberately don't. Then, if you point out that their refusal to do The Thing is a problem, you're "a nag" or "picky" or some other form of the problem. And if, after they regularly refuse to solve the problem and just do The Thing, you leave... well, you left. You quit. You filed. You're the AH.
It's a passive-aggressive game played by weak-minded people. The only way to win is to stop caring what they think and do what's best for you, and that's usually leaving the relationship because these types don't make good partners.