Ok

Im not going to say youre the AHole, but I dont think he was either.

From what you said (in other replies) is that he is usually the 'hangry' one, so I think because it was later than usual, he was getting peckish and needed something to eat and literally asked if you wanted some (of the snack). But then you got upset.

IMHO that was considerate because he was waiting for you to get there before making dinner, and was making a snack to tide you over since it was later than normal.

I just think it was a communication misstep here. I think had you said 'no thank you, I just want dinner - what are the plans' then he would have told you what he had planned.

Now, if he had answered 'I dont know' or 'well, what do you think' or something that made it clear he hadnt planned anything, then I would say he's the Ahole. But as you wrote it, I dont think either of you were.