I promise I don't live in a more expensive area. I live in the NW of England in a seaside town.
But secondary school uniform and equipment can easily come to £200 per child, then another 50 throughout the year.
Travel passes here for kids on the bus are £63 a month. That actually works out at £3000 a year for 4 teenagers.
Not everyone goes to university, no. But they don't usually decide until they are 16 and then you suddenly need to save fast to supplement their maintenance loan? Potentially 4 times over? Thousands with your husband earning 60k as they'd get the minimum amount. Martin Lewis did a great show on this for parents.
I've only given examples relating to education. When you're young and everything is about toddler groups and starting family life retirement and universities and driving lessons etc seem a lifetime away. They're not. And that's the reality.
It's not "piling on" to point out the potential financial pitfalls of being a SAHM or choosing to have a larger family on an inadequate income.
Many women look back 15 years down the line from the OPs situation and wish they'd thought and planned ahead a bit more.