It's none of his business what you decide to spent the money on.
The amount he pays is based on his income and is designed to keep the children in the lifestyle they would have expected had you stayed together.
You need to remove everything from the list and tell him it's not relevant to him.
However for your own calculations bear in mind your costs include feeding, clothing, housing, water, electric, insurance, car expenses (petrol, service, MOT insurance, childcare, xmas & birthdays (their own and going to friends which requires a gift), days out, treats when out, toys and activities to stimulate them, dvds... You can add lots of things if you think about it. Then there's big purchases like car seats, buggy, bedroom furniture (cot to bed, storage etc) and decorating. And if you want to be really pernickety you can include your time for being an unpaid childcarer, your extra time spent cleaning, cooking, washing, caring...
And as they get older you may find you pay less in childcare (you will still need to cover the holidays and before/after school), but you will get extra expenses at school - uniform, shoes, pe kit, various trips, photos, dinner money, donations, school events like fetes & raffles (to name a few). Plus they will want to use your computer/internet access, have a mobile phone (when a bit older), have more trips out to cinema and the like, pocket money, you wil be ferrying them around more to clubs and activities (swimming, brownies/cubs, music/dance lessons)...
You absolutely do not have to justify your costs to him. Not now not ever.