As other people have touched on and in my experience the men in the scenario seem to leave each other alone whereas the women don’t which is where most of the problems come from.
My dad never asked anything of my stepdad they were just polite whenever they saw each other, contact was consistent and rarely changed
My stepdads ex on the other hand was high conflict/demanding did the whole sending crap clothes and nice ones bought by my mum/sd never coming back, specifying uniform from a certain shop when I got mine from Asda, certain brand trainers (I got nicks) etc changing contact, constantly asking for money, putting in new claims through CMS as she thought she’d get more ( she was actually entitled to less) demanding my ss had her own bedroom and I share with our half sister so a room sat empty most of the time . It never stopped and that was just what I saw as a pre teen.
Im also having a similar experience as a sm.My exh is polite and asks nothing of my dp. I get £150 a month as he doesn’t earn loads, half of big school trips, half of uniform and ask for nothing more our co parenting relationship is low contact as we really don’t need to discuss much and no conflict.contact with my ds is consistent.
My dp ex is hard work…constantly asking for more money and she gets a considerable amount as well as dp paying for clothes, trainers at £150 each, uniform, hobbies, pocket money, phones, bikes etc asks for money for a takeaway as she’s got no money till pay day. My old school view is you simply don’t have a takeaway if your skint. Contact changes constantly she demands we do certain things on our time with them but it’s the emotional side of things that’s the hardest. She involves them too much in things kids shouldn’t know about like money and disagreements between her and my dp so there is constant drama with his kids and it feels like he is always taking them out to talk to them to try and smooth things over when they shouldn’t even be involved. I’ve also been brought into things saying I don’t do enough, talk to them enough etc which is ridiculous.
Anyway both exw in my experience demand far more of the sm, with the stepdads having no demands from the dad. I think there is something to be said for having consistent contact as well as it removes a lot of the need for communication and risk of conflict over changes.