My girlfriend (27f) isn’t listening when I’m (29m) telling her I won’t be going to another music festival with her

Music festivals aren’t really my thing and they’re not something I had any interest in. My girlfriend had been to a couple before we had met.

We’ve been together for 4 years now and last year she kept talking about wanting to go. I tried explaining they’re not my thing and I’d rather spend the money on something else.

We ended up agreeing to go to one that is a bit smaller than a few of the ones we have in the UK but still fairly big.

I told her this would be the only time I’d be going to a festival and after the festival she drops the notion of going to another one with me and she agreed.

We went to the festival last month and while it wasn’t terrible, it wasn’t really for me. My gf is already talking about going back next year.

I reminded her of our agreement and said if she wants to go next year she can take a friend because I won’t be going back. I mentioned it’s too much money for me to be spending yearly for me not to be enjoying myself.

I pointed out the cost of the festival and everything around it could have gotten me a week abroad which I would have enjoyed a lot more. I reminded her she agreed to not keep bringing up festivals if I go to one with her.

She said I wasn’t being fair but I pointed out she wasn’t listening. I’m not willing to waste my money to go to festivals when I’m not going to enjoy it.

Does anyone have any advice on how best to approach the situation or have any other perspectives on it?

Tl;dr I agreed to go to one festival with my girlfriend and no more. She agreed to this but is now calling me unfair for refusing to go to a festival with her next year. She said I should be fine with going.