Try relaxing and think along the lines of, "if I had $20 (or whatever amount he's wanting to spend) what would I buy?" Surely you can come up with something. The books are just for you. I don't understand why he won't accept that.
I have difficulty coming up with something because I usually buy whatever I want for myself and at nearly 70 I have most things already. Back when I did have a list, it included candles, cologne, scarf, always clothes. costume jewelry, a gift card for books or clothes, fancy socks, a cell phone, a tablet, new fluffy towels, new kitchen towels, sheets. Even tho towels and sheets aren't necessarily personal they are used primarily by me and I enjoy having new ones and they aren't necessary.
I suggest that you could ask for him to fix dinner one night/week or month; to do the dishes once a week; or some other task that you'd feel good about not having to do yourself.
I've asked my family to all get along and I won't be getting that for Christmas and since I don't have a list I'll be pleasantly surprised at what they come up with. I've told them I don't need a gift and they agree, lol, that my house is full enough but they will think of something and I'll be pleased. I much prefer giving gifts than receiving them.
And it sounds like you're that way too by asking for things to help with the kids. You'd probably be most pleased if he bought you those things. Perhaps if you keep insisting that is what you want he'll do it.