Am I being unreasonable about our household spending?

[CalmCanyon]

I’m interested in getting a reality check on our household spending because I’m struggling to work out whether I’m being unreasonable or whether our costs really are out of line.
We’re a family of four plus a dog in the South East of England. One of our daughters is at university and isn’t home most of the time, and her spending isn’t included here as she has her own finances.
Our monthly spending is roughly:

• Finances (mortgage, council tax, utilities, insurance, phones, broadband and other regular household bills): £1,833
• Groceries: £869
• Shopping (clothes, household items, Amazon, etc.): £583
• Transport: £253
• Eating out: £109
• Home & Family: £78
• General: £68
• Children: £32

Total: around £3,825 per month. The grocery and shopping figures are what concern me most. I don’t actually do most of the food shopping or day-to-day purchases—my partner does. As the sole earner, I see the overall numbers each month and I’m finding it increasingly difficult to make the budget work. I’ve tried to have calm conversations about our spending and whether we could cut back, but they usually end in disagreement. From my perspective it’s becoming a financial issue; from hers it doesn’t seem to be viewed in the same way. Unfortunately it’s started to affect our relationship, and at the moment it feels more like we’re housemates than a family working towards the same goals. I’m genuinely looking for outside perspectives.

At this point I don't think I'd be wanting to marry someone who was openly saying they'd leave me if they could, was not interested in having any meaningful conversation with me about anything, and was expecting me to bankroll them ad infinitum.
Presumably the OP's partner had autonomy to😊 agree to children without marriage, and also input into registry office v big do so I'm not sure OP is necessarily to blame for that.

Op, it sounds like you love her. Try to love her even a little bit more. I know it all seems awfully hard now but good times will come around again. She'll hopefully get back on track once she's over the health scare and manages to reinvent herself career-wise. Give her the time and grace she deserves as your partner in life through thick and thin.

Maybe she ought to love him though a bit more and stop getting themselves into near debt?

As you asked, the usual reason that a SAHP feels undervalued and offended when a wage-earning parent asks them to contribute financially is because in their view they are already making at least an equal contribution of their labour to the household team (possibly many more hours of more physically demanding labour), and so this request strongly implies that none of that is actually being seen and valued by their supposed partner and they are instead being seen as contributing nothing.

In this case active SAHPing seems to have long past and so perhaps you should talk to her and understand what she specifically believes her current contribution is to your household team - it won't be nothing, but it might be illuminating to see what areas you have a mismatch of perception on.