A bad marriage can grind you down. Chip away bit by bit.
I have a good friend who I've known for 12 years. Shd been married for 3 years by then. Her marriage struggling already. His drinking and selfishness, flirtations/affairs with other women.
The marriage survived and has survived 3 affairs - one serious where he did leave her. Unfortunately, she took him back. Again. Believing his false promises of it being a mistake and of course the suicide threats he made.
Earlier this year, it did look as if she would leave him. Lots of reasons. Of course, he eventually talked her round. She is now preparing to move away with him to start yet another 'new' life.
Away from her family, friends and even colleagues. Who put ideas in her head as we don't understand him.
They have no children. She earns good money.
What I'm saying is this: some women stay as they are so ground down. A manipulative coercive man also knows to temper this with over the top declarations of love, that they are soul mates, that outsiders don't understand their marriage.
She hasn't the strength to leave him. I think that's the truth for many.
We need to raise our kids to recognise coercive control for what it is. Sadly, being blinded by love can render anyone vulnerable to this behaviour.