Hey AITA, long time reader, first time poster.

This happened in August last year, but has recently come up in conversation with my friends, so I wanted some outside opinions about it.

My ex (let's call her Dani) and I broke up in late May or early in June last year, but we were trying to stay friends after as it was hard losing someone so close for both of us. (We dated for roughly 2 years)

Dani and I would go get food, chat about what's been going on, new people we were seeing, etc. We'd probably meet up once a week, just to chat and joke.

Dani would talk about new guys she was seeing, I'd help her (genuinely, I want her to be happy) by giving some advice about how to pursue them, or once in a while say maybe this guy wasn't a good idea for her. 

On this particular day, I really wanted to talk about a new girl I was super into (call her Jen). Jen and I are co-workers, so Dani kinda had an idea of who she was. 

Meal starts off fine, Dani is talking about a new guy she's with, I'm cracking a couple jokes, all is normal. Soon, I start to shift the conversation towards me and Jen, and Dani has an immediate tone shift. She gets a little cold, starts being rude and making some pretty harsh comments. 

I don't notice this right away (I'm 20m and pretty ignorant tbh) so I continue talking. Soon Dani calls Jen a bitch, and starts saying some REALLY off things about her, who she really doesn't know. Saying things like "she's just a bitch" "she won't like you" "she's gross" yada yada. At this point, I'm a little more than offended, so I tell Dani I'll drive her home, because I'm done here and I really don't wanna talk to her anymore.

We take her food to-go and start driving to her house. On the way I tell her I thought it was pretty shitty of her to just beat up on this new girl who I really like, and Dani goes off about "am I not allowed to have an opinion? Can I not say what I feel?" 

Something about how she says this really heats me up, and I kinda lose my cool here if I'm honest. I shout at her saying she can have an opinion, but she's can can also try not being a piece of garbage when she tells it to me. 

Now I'm not exactly a shouting kind of guy. Most people I know have never even seen me mad, but I felt pretty wronged here. She was always allowed to talk about guys she was interested in, or people she'd slept with but I couldn't talk about this one girl I actually liked? 

After my little blow up, Dani says "I don't deserve to be *yelled* at, so you know what? You can just let me out right here"

Before she finished her thought, I had slammed on the breaks and just pointed to the side of the road. 

She gets out, slams the door (for context, we're about 5km from her house, and it was about 30°c or so) and I whip off. As I'm driving home, I see her keys in my cup holder, so I text her saying I'm coming by to give them back. The text conversation was pretty rough if I'm honest, both sides were pretty angry and it only made me more pissed.

As I get back to her house, shes out front, and I'm really not feeling talking to her. So as I pull up, I roll down my window and just chuck the keys in her direction. (I don't hit her with them, they land somewhere near her at her feet) and immediately start backing out. I can see she's giving me the finger as I leave and hear "enjoy the soup asshole." So I chuck the soup out the window after as I drive off. 

Now I know I probably overreacted, but I seriously feel I was justified. Or am I just an asshole?