Work it out or break up?

I’m 17 been w my bf 2 years. Lately things haven’t been so great between us. We’ve had plans together that he’s cancelled a few times to go get drunk w his friends.

Today I was talking to him about my prom and he said he wasn’t sure if he wanted to go. He said he’s “too old” and won’t “fit in.” He’s only 2 years older then me. Meanwhile I went to his prom when I knew no one and I was only 16 and they were all 18. I just feel like he’s being selfish. To make matters worse my dog took his new retainer and chewed on it. He got sooo mad, almost cried and then left in the middle of us hanging out.

What do I do 😭