OP you asked aibu. I would say yes, yabu.
You cook every day as you say (I'm assuming just weekdays - I may be wrong) but I expect your husband has some repetitive aspects of his job that he hates but has to do every day as well - many jobs do have mind numbingly boring parts to them.
I think that being on maternity leave means you cook. Having had 7 children I totally understand the alienating hell that a clingy baby can plunge you into, but this man sounds reasonable. He bathes and reads to his child daily after work and you cook. I don't think its particularly hard to plan and shop for a simple meal with one single 8 month old, however stressful they are.
If you really can't bear cooking, perhaps you should do the bath and read while he cooks, but that does diminish their time together. Or are you thinking he should work, bathe, read to and cook? Genuine question and not sarcasm.
Him "faffing" on the pc seems reasonable seeing as you can do this during the day and he probably doesn't get much chance to.
He is supporting you while you care for his child during the day and preparing a meal seems to be a small part of the general caring exchange.
Obviously, I'd give a totally different reply once you go back to work and I'd give the same reply if you were male, which I'm assuming you're not.
I think if a man on paternity leave complained about having to prepare dinner for his working OH there would be less support for this complaint.