So i went to a party with my girlfriend, who i was in a LTR type relationship with.

Her ex, who supposedly ruined her life and she doesnt speak to, was there. I didnt know what he looked like. She didnt tell me that was him, i found out from someone else at the party.

I said her name and motioned for her to come here. She turned her head but claims to have not heard me. She walks over and starts chatting with her ex. I tried to retain frame and calmly got a plate of food and sat near them and ate it.

I could feel myself exploding with rage inside so I took a lap for about a half hour to try to keep my head.

When i returned, they were standing very close and clearly enjoying each others company.

I walked up behind her and she kind of ignored me. I said I was leaving, and she could go or stay.

I tried to be stoic and not speak with her, but inside i was exploding with primal rage. We were an hour drive from home, and over the course of the drive i lost my shit and went full anger and told her all of the things she had done wrong.

At first She said her night was ruined, wanted to go say bye to everyone, had done nothing wrong.

Then she vacillated between "I did nothing wrong" and I am so so sorry.

I told her she had compromised my standards, lost my trust, and I did not want to be with her anymore.

I know I acted like a butt hurt little bitch and she will probably never see me the same, which I accept.

How would you have handled this better?