If she really wanted to get away she could.
Depending on the relationship - and I’m not saying that theirs is this as obviously I don’t know - if you’ve been under emotional abuse and coercive control for some time you don’t realise that you
need to leave, let alone want to. You don’t have your own wants any more. Only those of the controlling party.
You don’t think about leaving because it’s simply not a possibility as you know it, but more than that you’re convinced (because you’ve
been convinced, over time, very very well) that you can’t possibly manage on your own / you would be completely alienated by your family and friends and then no longer have the only person you currently have / you would be responsible for the person you love and who (you think) loves you being alone and - often - you’re told they wouldn’t be able to go on without you so they may end their life if you leave them.
Sometimes with a child involved they threaten that you’ll never leave with
their baby, or that if you do they will find you and take the child back and you’ll never see them again.
It’s rarely as simple as if she really wanted to get away she could.
As I say, I have no idea about
their relationship. Just my thoughts on one type of relationship.