How do women differentiate between a man being controlling/insecure and them disrespecting him?

I know a guy who is in a relationship with a woman who had a very controlling ex boyfriend. This guy is besotted with this woman who is like a 5.5/10 at best and has 3 damn kids! Now the guy is terrified of doing anything wrong or calling her out on anything in case she calls HIM controlling and leaves him. This woman basically walks all over him but if he backs off and becomes unsure if she's the one for him she comes right back saying sorry to him.

The woman does things like has male friends over for the night, is openly playful (flirty) with other male neighbours in front of him, etc. She will get her phone out and start texting and chatting to other people while they are going to a movie or something. He said she makes flirty comments about random men public. Things like that. To her it's no big deal.

I said to this guy that there's just no way i would stand for that sort of thing imo that's blatant disrespect, unless it's an open relationship, and yet she's told him that she hates controlling men like her ex and she wants to be able to just be her and not have a man try to change the way she is.

She said that her ex had ordered her to take down her social media and stop accepting men on facebook and that she wasn't allowed to look at any pics of 'hot guys' on instagram. She wasn't allowed to show her legs or wear low cut tops in public, etc

So where's the line in situations like that? It means a woman who has had a controlling ex partner can now effectively do what she wants and behave how she wants with the new dude and he's supposed to accept it because the other guy was controlling?