Still hurt and upset by breakup

My boyfriend gave me an ultimatum a few weeks ago when I told him my best friend invited me on her birthday trip. My best friend usually celebrates her birthday overseas and I finally have the opportunity to join her. When I told my boyfriend, he immediately got upset and said that if I go we’re going to break up. He has a history of being controlling and insecure, but he went on a trip with his friends a few years ago that I was okay with. I figured he would understand it was important for me to celebrate my friend’s birthday, but I haven’t heard from him since.

He also admitted to me that during his trip he “flirted and danced” with a girl he met. On top of that, he told me that one of his friends who was in a relationship cheated on his girlfriend with a prostitute he found online. I can’t help but think that he is projecting whatever happened on that trip to me. I feel like I shouldn’t feel sad or hurt, but I do. I still want him to contact me even though I know he isn’t being very fair. Part of me still feels like the break up is my fault.