What should I do?

Me and my boyfriend of around 5 months went on a trip this weekend with his family ( mom, stepdad and brother) to go watch an event for his family. while there he acted completely different, i have noticed everytime he is around anyone else like his family or friends he’s acted different. he is not a very smart guy and i feel like he says dumb stuff all the time which i don’t know what to reply with so i don’t. he got mad at me for this later on and starting talking to his friend which i heard so i left with my other friend and went and sat in a different place. he got mad at ME when people at the event would ask for my number, when i told them no and made it clear i had no interest in them. i hate jealously and acting like a child and this is excatly whag he did this weekend which make me feel VERY icky. i think this kid and me are meant to be friends but i don’t know if i’m just overthinking or if i’m valid. and if i do break up with him how do i do it? we have a winter formal on this coming saturday which is abt 6 days away which he already bought me tickets for so do i do it now or after? i know i can buy my own but woudl i give him the ticket back or what?

I feel like it’s also good to add while on this trip he got in a fight with his mom over soemthing he said, we were at a restaurant and when walking out because it was time to leave he walked out there and left me with his little brother and step dad who i barely know. i don’t want him to think i’m breaking up with him because of this fight and it was weird but i don’t know.

Also he talks to his friends about having “w rizz” which is a middle school thing in my opinion, but won’t even make a move on me AT ALL unless someone brings it up