I agree with this.
My Dads second wife was awful, and his third (current wife) is even worse. Not to mention the four girlfriends in between.
But he’s even worse than the pair of them combined, and my anger lies with him, not them.
Conversely, my step dad is great, was married to my Mum for 15 years, they divorced 7 years ago and he’s still very much a part of my life.
It’s easier for kids to blame the wife. Because accepting that your Dad is a piece of shit is really, really hard and destructive to the soul, frankly.
I was about 10 when I realised it all the shit started and ended with him, and in my 20s when I realised he deserved his horrid wives 😬
My kids have a wonderful step mother, thank fuck. She’s like the Cool Aunt they don’t have cos I only have brothers. What happens behind closed doors, I’m not a party to, but my kids adore her, and that’s more than enough for me.