AITA for getting angry with my boyfriend?

It all started last Tuesday. He rents a room behind my house (my mom rents it to him since he's from out of town and lives there because of the university). Since everyone in my family knows him, it's normal for him to come in through the back door to eat, hang out, or help out with things we ask him to do from time to time.

On Tuesday night, he came in, and my mom asked us to go get some tortillas for dinner. We went to the place, and he asked me, "How many should we buy?" I told him to buy any number since there would only be four of us eating, and he was the one who ate the most. He bought six, told me to buy two more, and I told him it wasn't necessary. He said, "Fine, but if your aunt asks you for one, you're going to give her one of yours because I'm not giving her any."

To give you some context, I have an aunt who visits us often, and I have a strained relationship with her. I don't like her very much, my friends don't like her, and my boyfriend doesn't like her either. She was going to stay for dinner, but she wasn't supposed to eat tortillas, so I thought it was fine that he only bought six. But because of that comment he made, I told him, "Okay, eat as many tortillas as you want; I can buy as many as I want," and I bought two more.

We went back to the house, I made dinner, and when he took his tortillas and left mine, I told him I wasn't going to eat. He asked me what was wrong, and I told him I didn't want his tortillas since they were his. It wasn't a big deal; I wasn't really angry. While I hadn't liked what he said before, that feeling had passed, and I was just teasing him.

He said he didn't understand why I was upset, and I told him about his comment, that I didn't like it because I felt like he was implying that if there weren't enough tortillas for everyone, I shouldn't even think about asking him for one since they were his. I know he didn't say it like that, nor did he say it in a mean tone. I took it badly at first, and then I told him about it when he asked.

The thing is, he didn't say anything to me. He went to his room and locked himself in there for the rest of the night. Since we're at the same university, in the same major, and have the same schedule, we usually ride together on my motorcycle. I went to see him early and asked if he was ready to leave. He didn't answer, and after a while, he left without saying anything. I called him to ask why he hadn't told me he was going to walk, since I was already running late because I'd been waiting for him. He just said he'd let me know before I called, hung up, and didn't answer when I called him again. He didn't speak to me the rest of the day, or even look at me.

My classmates noticed this. The same thing happened yesterday, Thursday. I went to find him and asked if he was walking, and he said yes. I asked if he would save me a seat next to him or if he wanted me to save one for him, and he said, "There are plenty of free seats," and left. After class, I followed him and asked why he was avoiding me. He dodged the question, saying he wasn't avoiding me, that everything was fine, until I asked if it was because of Tuesday. He said yes, that everything was fine between us until I acted like a little girl.

I told my classmates that he wanted space because he was upset with me (I didn't tell them why since they're a bit gossipy, and I didn't want any rumors about something so silly) because of a joke I made. They told me he was being immature by ignoring me like nothing had happened without saying anything first. And if he didn't like my joke, he should have told me from the beginning instead of just ignoring me.

The truth is, I understand why he was upset. My behavior could have been better; I could have said nothing about those tortillas, kept quiet, and everything would have been normal. But what hurts, and this is where I wonder if he's also acting badly, is how he ignores me. He does it very well, acting so perfect that I don't even exist around him, and everyone noticed. It doesn't hurt that he wants space; I understand that. What hurts is that it's so easy for him to pretend my existence doesn't matter when he means so much to me.