My (separated) ex-h has my children one night a week at my house (cooking them dinner out of my freezer which I have bought with my money) and also has them overnight one night a week at his house. When this arrangement first started in September last year, I sent the children to his house with their overnight bag containing night clothes, clothes for the next day, toothbrushes, toothpaste, nappies, wipes, etc.
After about a month I told him that although he pays me maintenance for the three children it seemed daft me putting in a toothbrush each, toothpaste each (they like different ones), nappies, etc. and just told him that when he did his next weekly shop he should buy a pack of nappies, a toothbrush, etc.
Now I don't include toiletries, nor bed clothes for the elder two, but I do still include bed wear for the youngest.
Of course you are not being unreasonable, whether you are better off than he is or not.
Ex-h is taking the children on holiday on 10th August with his girlfriend and her 15 year old daughter to an all inclusive holiday in Zakynthos. I wondered how he could afford it - but then I realised he is not paying a mortgage as he is living in his girlfriend's house and it is rented (cheap rent too as it was her nan's house).
I don't envy him his holiday thinking that he is better off than me - I am off with my mum for two weeks kids-free although I am going to miss them like mad (start another threat, feel a bit worried).