Crazy irrational behavior

I changed my phone number today.

Before I did I had my friend listen to his last voice mail. The one where he was very sweet and wanted to get back on track. My friend thought that my reaction to him having sex with someone was unfair, given that we were broken up for months. I see her point and know that I did become a crazy person. It was as if my reaction was out of my control; truly irrational. I couldn’t just sit with it and consider what to do. I was so triggered. I don’t normally function like a crazy person and am confused that I did not handle it like an adult. But that’s how I always reacted to him. I am not trying to rationalize the situation as an opening to break NC. I just am asking you out there what you think.