Well, I have 50/50, so no maintenance technically due. However, I still pay some because I earn more, and I want to make sure my kids never go without.
Unfortunately, my ex just takes.
She has never bought a single item of school uniform - I buy it for both houses, for two kids at secondary school.
She has never paid a penny towards a single school trip - the residentials and the overseas trips all get paid for by me.
She barely even gives them any money for their lunches on the days they're with her - they always end up coming to me for money.
They both have expensive hobbies, which cost me well over £100 per month for each of them. She very generously "allowed" me to reduce the voluntary maintenance that I pay her by £10 per month per child as 'her' contribution, and now makes a point of emphasising to the kids how she is paying for their hobbies.
She doesn't do anything with them. When they're with me, we have days out and have fun together. At her house, they end up sat on their phones in their room.
They regularly come to me to say there's something they need at their mum's house, but she has refused to get it for them because she "can't afford it". However, they also point out that she then immediately bought herself something new (kids notice everything - they're not stupid!).
So I'm paying for pretty much everything, because she knows I will never see my kids go without. Pretty damn galling, though - especially after she took a huge divorce settlement.
So, let's not badge all dads as feckless NRPs - the majority of us are out there, consistently doing the right thing, and putting our kids first. Even when their mother refuses to do the same.