Disagreement

My boyfriend is talking about going to Bonaroo (a music festival) with some friends later this summer. I told him that I didn’t want him to go because I was unable to go as well as it being a big expense and he has other trips planned this year. He said that if He were in a similar position he would not prevent me from going. I just really don’t want him to go and the thought makes me anxious. I saw him texting one of his other coworkers who also is going (separate from him and his friends I believe) and he asked her if he should just put money down on a ticket even if it made me ‘a little bit salty’. I don’t know what to do or how to make him see how upset this makes me but I’m literally pulling out my hair with frustration. I told him I would be happy to go next year!