If you take a step back/cut your hours, your workload will ultimately increase not decrease. And not just in the short-term but for years to come.
You will be responsible for all nursery drop-offs/pick ups. This will evolve into being responsible for all school drop-offs/pick ups. Your husband might "help" you as a favour sometimes, but only if you present him with a fully ready, dressed and breakfasted child that literally needs to be handed over like a parcel.
You will be responsible for all nursery and school organisation and admin - packing nursery and school bags, making packed lunches, liaising with nursery and school, following up on any concerns, parents' workshops and evenings.
You will be expected to cover all sick days, unexpected nursery closures, staff inset days etc. You will be responsible for organising school wraparound care.
The housework and mental load will be mostly yours since, after all, you have days "off" with your little one to sort all this stuff out. Never mind that you worked until 11pm the night before to meet a deadline or that you've spent the day running around after an active toddler.
Your husband will assume that his relaxation takes priority on weekends since you work 'less' than he does.
He wants you to take a step back to make his life easier, not yours. The wisest thing you can do now is fight for an equal allocation of work, childcare and household chores.
I am speaking from experience. I am clawing my way back slowly from having fallen into this pattern.