I don’t have pets but I didn’t think cats needed that much looking-after day to day
Not all cats are trouble free day to day.
Of course most of them are, most of the time, but even those need daily feeding, watering, worm and flea treatment, taking to vets if necessary and for annual vaccinations.
Then some cats need daily medication, there might be a litter tray to clean, if they are sick, they need to go to the vet, they need cleaning up after - cats might be clean animals, but they do leave quite a lot of muck and fur on pretty much every surface they come into contact with, so extra vaccuming, laundry, they damage curtains and soft furnishing, the bring in prey that could be in any state from alive and well and it escapes and makes a new life for itself behind your fridge to dead and needs disposing of and anything in between, you need to make arrangements for their care when you go away.
It's certainly noticeable if there's two people in the house and one isn't doing any of it. Eg if the OP went away for a few days, could he be trusted to feed her, sort the litter tray, any medication, deal with half dead mice, keep an eye on her to make sure she's not sick, without any reminding or prompting?