AITA for telling my boyfriend he made my vagina dry up?

My boyfriend and I go out for dinner pretty often and it’s usually a nice experience. Tonight we went to one of my favorite restaurants with another couple and everything was fine during the meal. It’s not a super fine dining place but relatively nice (entrees in the $25-$35 range)

He ordered a Diet Pepsi and his friend ordered a regular Pepsi. The friend’s soda came in a glass bottle and my boyfriend’s came in a smaller can. It was probably a 3-4 ounce difference.

When the bill came, he noticed that the price for both sodas was the same despite his being smaller. He asked the waiter about it and the waiter apologized but said all of the sodas are priced the same at $4. I thought that would be the end of it but my boyfriend’s then asked if he could talk to a manager.

The manager had the same response and my boyfriend was upset he wouldn’t take it off the bill. He kept complaining to the manager, and I was starting to get embarrassed so I offered to just pay the bill, so we could be done with the situation. He didn’t let me pay and continued to have an attitude about it. He left a tip but it was such a turn off for me that I told him my vagina completely dried up.

Obviously he didn’t like that comment and took offense and said he was standing up for himself. There are some circumstances where I can understand complaining but this went on for 10 minutes. Am I crazy or is a $4 soda at a nice restaurant a crazy hill to die on?