Just remembered the first Mothers Day after I'd had my first child. I thought it was such a big thing, being the first one, and I assumed that DH would realise that and arrange a little card and a bit of pampering (well, cup of tea in bed and a lie-in!). Even though he would be writing on the card himself, I just assumed he would want to do it to show his appreciation of the fact that I was doing so well in my first year of being a new mum to his son 
Well, I got nowt, and was really upset. My MIL was embarrassed at his "failing" and rushed out to buy me something little (which was equally embarrassing) and in fact did it for a couple of Mothers' Days after that till she could see that he was finally trained and organised it himself!
But DH's explanation for the lack of card in the first year, which he thought was perfectly valid, was that he didn't understand that he had to buy a mother's day card on the kids' behalf - he understood that they would make cards etc at nursery and school when they were a bit older and then just organise it themselves when they were past that stage, but until that point, whilst they were babies and too little to write/colour on a little card themselves, he just really didn't understand that he should do something. He was mortified when he realised I had expected something, and especially when his mother went out to buy something for me!
Even now,though, I wonder whether he had a perfectly reasonable point!
Anyway.....after that waffle, what I meant to say was that what one person sees as perfectly reasonable behaviour, another person would see as being the total opposite. But it's not done out of nastiness. And in your case, OP, it wasn't done through thoughtlessness as he had already bought you a card and present and demonstrated his thoughtfulness that way.
I still agree with Colditz (that a grown woman expecting a big fuss and cake on a normal, non-biggie birthday is a bit strange), but each to their own so I think you should say well in advance of next year's birthday "This year it would be nice if for once you could arrange a meal out/babysitters for my birthday and you know how I love cake, so a birthday cake owuld be nice too, and it's kind of wierd to buy your own." And see what he says.