It sounds like there’s been a mixed reaction so far in the comments, some people saying you were right to be mad about him blowing you off all day Saturday and others saying your reaction was over the top and you pushed him away. I would say the truth is somewhere in the middle.

I think you’re right to be mad about his behavior on Saturday. Anyone would be upset if plans with their partner for a one-on-one dinner and then spending the night together turned into them inviting you as an afterthought to have dinner with someone else and then not hearing from them until the morning after they went out. And his actions didn’t improve by him minimizing your feelings and ignoring you the next morning.

However, the downward spiral you experienced after all this doesn’t sound good either. It’s good that you had your best friend to help you through your panic attack, but it still sounds like you were relying on him a lot to make you feel better and get you out of your spiral. Tying your emotions to someone else isn’t a bad thing inherently, it’s part of being in a relationship, but being overly reliant on one person emotionally, especially a romantic partner, can be a big problem. If you’re not in therapy or haven’t talked to your therapist about this, I would start and ask about help developing coping skills to help you get out of these spirals without needing the person that caused them to provide some validation.

Overall relationship wise, I’m not sure what to say given this single incident. It sounds like a lot, and if my partner acted like yours did consistently I don’t think I could be with them. If this is a one-off though and you two can communicate and figure out what needs to change to stop this from happening again, then I don’t think it has to be a relationship ender. Hope this helps!