Let us use the example of my sister's BastardEx as a case in point. Granted, he is an extreme version, but only that- just a variation on a spectrum of bastardy.
Bex abuses my sister. She stays. Bex deconstructs my sister's self esteem and personality. She stays. Bex tells my sister she is worthless. She stays. Bex threatens and intimidates my sister. She stays. Bex hits my sister and tries to strangle her. She stays. She stays because having grown up with an absent father, she strongly believes that families need fathers.
Then Bex picks up their 3yo slaps him, and throws him across a tent, before taking my sister's car, leaving her in the middle of France and pissing off. My sister at last realises she has to go.
She goes back to collect her and the children's stuff. He basically does not allow her to take anything, begs her to come back. She leaves.
Fast forward through months of abusive stalking, kidnapping of their son (there is also a daughter who is never the focus of her father's attentions), more threats, damage to her car, damage to her house, damage to her and her phone when she went back to their house for a birthday party for their son, blackmail, abusive phone calls, texts, yadda yadda yadda.
Past that, to the eventual family court hearing where tbh my sister would have been utterly in her rights to tell him to fuck right off and ask for supervised contact only, where custody arrangements are arranged and he agrees them, past that again to now, 7 years on, when Bex will never ever, ever keep to an access weekend because the court was "on her side", still turns up to "see the kids" at 10pm on a school night, still tries to refuse to take his daughter out as much as he can get away with, and still he uses the children as pawns, saying he'll come and then not turning up.
After all this, my sister still believes that her children should have contact. She wants them to make their own opinion. She still believes that families need father, even a cunt like this. She has to manage her children psychologically to an unimaginable degree, taking everything on herself and trying to make sure they are unharmed by it. All the while working full-time (it goes without saying that Bex pays not a penny in maintenance) to pay the new mortgage she had to get when he stole all her savings, pay the bills and put food on the table.
And still he whines that everything is done on her terms. So forgive if I issue a hard little derisive snort of laughter when I hear blokes whinging on the radio about how hard done by they are.