"I think in this instance, it is as much about the OP (and many posters in here) feeling entitled, as it is the husband being 'controlling'. If this were a car... would your responses be the same?
-puts car in shopping basket-
"Put it back, we don't need another car"
"Ltb, your dp is so controlling!"
I actually pity some of the partners in here... Any partner is allowed to say no, man or woman, without fear of being called controlling. A healthy relationship is about discussion."
Ok, so first of all, a bottle of milk is not comparable with a car. Yes, if OP just said, "I'm buying a car" then it would be appropriate for him to freak out. But I think it's interesting that YOU think it's appropriate to put a car and a bottle of milk in the same category, because it shows that your thinking on this issue is distorted if you can't distinguish between these types of purchases. One is a large purchase that people only make every few years and that usually requires a significant portion of the family budget, such that buying a car may prevent other, more essential budget items (food, heating) being bought. The other is a small purchase that people make multiple times per week. One is nonessential for life. The other is food, a basic necessity of life. One requires legal obligations such as getting MOT, insurance, etc. The other confers no legal burden. For those reasons, it is appropriate to expect a discussion of a car purchase before it happens, but inappropriate to expect one before a purchase of milk happens.
Now, if the couple is broke to the penny such that buying another bottle of milk is going to prevent you from paying the heating bill, then, ok, you are in a special circumstance where every tiny purchase must be planned and discussed. But, that is very unlikely because milk usually lasts a while in the refrigerator. If you don't drink it tomorrow, you'll drink it the next day. Consequence: you had planned to buy more milk on Friday, but since you bought extra milk on Tuesday, you skip buying milk on Friday and instead use up the extra milk that you bought on Tuesday.
I also am concerned about your claim that "any partner is allowed to say no." That is not the case in all situations. In some situations, yes. Any partner is allowed to say "no" to unwanted physical intimacy, for example. Any partner is allowed to say "no" to being taken somewhere against their will. But why would any partner be allowed to say "no" to the other person buying food, which is a necessity for life? So I would say that, no, any partner is NOT allowed to say "no" to the other person buying food. An adult telling another adult, whether or not they are married to them, not to buy food, especially normal food that is part of the usual family grocery list, is indeed controlling. It's the very definition of controlling.
I appreciate that you think the husband was partially wrong here for the way he phrased his disagreement. But the OP didn't actually say "Tough sh!t" which would indeed be an escalation. What she said was it was her choice, which was true, and highlighted the controlling and inappropriate nature of his command, hence defending herself from his unacceptable behavior. She is allowed to stand up for herself when his behavior is controlling and inappropriate! And, if it's a one-time thing, then no harm done. But if this is a regular thing for him, then absolutely there are red flags here. Women who are not allowed to shop for normal groceries without getting specific permission from their husbands for each item, absent abject poverty wherein survival requires detailed management of every penny of family budget, are being abused. That is my opinion.