I think you should start by breaking down your current joint costs including everything (housing costs, bills etc.) against your earnings.
For us, we both went part time and I worked evenings and some weekends. The way the tax system works meant that we were better off. With breakfast and after school clubs for our elder child, along with extra fees for early drops and late pick ups at nursery, it wasn’t worth working full time. Not forgetting the extra rushing around.
You can claim back childcare vouchers through work which saves a bit as does funding for children once they reach 3 years of age if your joint earnings don’t exceed £100,000. My mum also looked after my son one day a week. Once he turned 3, he did a few days at nursery with the funding covering a large part of the fees.
It was tough juggling everything but the time has flown by and enabled me to take my son out to different places during term time. Many churches run community events although stay at home dads are still rare.
4 years is nothing and I don’t regret halting my career or the impact on my pension.