You can end up spending a lot but I’m a big believer that you don’t have do be doing special things every day.
When mine were small we usually went away once or twice in the Summer which broke things up.
Then I’d do maybe one special day per week which could be a theme park, cinema, swimming, a farm. Sometimes this was free because you could do local free swimming and dh gets free Odeon tickets through his bank, we take our own popcorn.
Then maybe one day per week having a play date.
The rest of the time it was just a walk, park, feed the ducks, ride bikes or scooters. Perhaps I’m lucky but we have loads of completely free parks nearby where parking is free and some even have free splash pads. We could spend hours at the park.
Then we’d usually have lazy days where we’d stay at home, I might get the dc involved with some gardening, sorting their bedrooms, make a pizza on a base and watch a movie, I let them have way too much screen times some days but so what.
Sometimes I’d just drag them on a walk to the supermarket to get a few bits and grab a box of Rice Krispies and some chocolate and make cakes
Edited to add why is your dh making comments? Does he take his annual leave to care for the kids too and think of some ideas because he should do.