But whatever your household income is, if I earn the same for my household, our households will still have vastly differerent incomes after tax in the current system: mine being far lower.
So you benefit from cheaper living costs by living together. You have 48 hours per day to spend on earning money/ career progression/ spending time with your children and reducing childcare costs by doing so (if you have children). A single parent has only 24 hours per day to do these things so will have higher costs than you and then even if they earn the same as your household will be taxed more than you are.
Anybody who thinks that is ok is mad, frankly.
And as a PP said, it's very depressing that people would rather scrap over division of crumbs than recognise the basic unfairnesses of the system (even those that, if rectified, would not benefit them personally) and campaign to get these things changed, for everyone's benefit. I highlighted many other issues not just about single parents but tax reform in general earlier in the thread. So many people's refusal to accept basic logic and fairness about an issue just because it doesn't affect you personally is, in my opinion, a large contributor to how we've ended up in such a mess as a country. Scrabbling over selfish personal gain and no willingness at all to look at the wider picture and what has been proven to work in other countries and take a long-term view in terms of productivity and what will benefit everyone in the longer term.
I should not have been wasting time trying to argue it, I know nobody cares about single mothers and this thread has shown it so plainly, with one or two exceptions. Same old attitudes, same old prejudices, same old "but it would be so unfair to me if we stopped penalising them and making them pay more than me and my husband do!". 🙄🤯