I think that's a pretty romantic view of abusive relationships.

From personal experience being dragged into other women's drama there's never just one psycho in any relationship, always two.

It's pretty common that in abusive relationships you have a narcissist man who is obsessed with his ego, pride and self image and a BPD woman who has a terror of abandonment. That's why these shit shows keep going. Not because this narrative that it's a slow build up they don't see coming but because the woman has already got a mental illness which means they will cling on to a partner no matter what even long before they meet their abuser. And that's why they go back even after they have escaped and are safe (which is something the feminist theories can never explain).

They don't pick the wrong person, they are the wrong person. This is why they will tend to end up in those types of relationships over and over again. These guys will purposely hunt these damaged women out but also BPD women will only want men who give them these big displays of emotion because it makes them feel important and wanted.

You can see from his post she has a whole list of illnesses which is a way to make him feel he can't leave and abandon her. Him becoming trans might be great from her POV because she'll know no other woman will want him. But him screwing around is the opposite of that because he could meet someone he likes better so that is not OK.

Edit: Just a note that I actually have a family friend going through this at the moment. She goes through the motions of getting restraining orders against him and then takes him back. Now she's got pregnant by him, which is a great tactic to tie him to her. She berates her family for not being nice to him after she's spent a months telling them all how terrible he is and that's she's scared of him. There's a good chance he'll kill her because he's already put his hands around her neck but no way to keep her away from him. You aren't allowed to section such women any more and if the police take him away she just chases after him more because her main concern not being rejected (not her or her kid's safety).

And we all know full well were this comes from. Her dad is a narcissist who was always the most important person in their house, ahead of the kids who actually needed looking after. So she was set up from a young age to chase and dote on such men. But of course her close family can't address that fact because then they would have to address their father's issues (which he still very much has). They have to pretend the situation just makes no sense instead which means they can't take the action they need to.

And this is like the third time she's had a relationship like this but it's the worse one yet.