Asking “Can you afford that?”
If he’s buying it for you, he can afford it. Even if he can’t, it’s clearly so important to him to buy it for you, that he’ll find some way to afford that. The question, “Are you sure you can afford that?” is terribly emasculating for a man. It tells him that you think of him as some poor broke dude. No guy wants to feel that his partner sees him that way.