My boyfriend's super flakey

So I'm in a relationship and he only lives like 20 minutes away, and he keeps saying he'll go to things to support me like my swim meets and then he'll just not show up and like halfway through he will text me and be like,"oh sorry, I can't make it to the meet or any of our other plans after" and then I see snapchats from his friends and he's having a party at his house and I'm not sure if this should bother me or not, but I'm really frustrated because I told him he doesn't have to go and he can just say if he doesn't want to but he just keeps saying he's going to and then just canceling completely last minute, and it's just really frustrating and I'm not sure what to do, I mean it's a really new relationship and we've both only been in 1 other relationship, so I'm not really sure what's normal or what to do with these sort of things