AITA for refusing to go to Disney land with my SO?

This happened back in 2019 but has still been on my mind and I want to know if I had been in the wrong. I have since broken up with my then partner (male 21, in 2019).

So, back in 2019 when I was 20, my then partner 'Lennard' (fake name) had asked me in June if I would come with him on a family trip to Disney land and universal studios. he said all I needed to pay was for the $500 plane ticket and his parents would pay for the rest. This was a very nice offer but I had just moved to a new city with my sister and had paid my portion of the down payment and first and last months rent and pet rent with my savings and was still looking for a new job in the city. I was living off my savings and new that what work I could find wouldn't let me recover my savings before the trip which was the week of New Years. I know I had time to save, but I had new expenses to manage and told him that I don't think I'll be able to go. He was upset by this and the next few months kept asking if id change my mind and I told him that I still couldn't. A few weeks after the move I had started working as a host and then as a cook at a different restaurant, making at most $13 an hour. He kept telling me it was only $500 dollars and that he didn't understand why I kept saying no, but to me it wasn't just the $500 dollars it would be an additional $500 that I would have lost not working for a week. I had tried to explain to him that my sister and I were struggling because of the move and we had to have a tight budget but I was not and still am not the best at communicating. He had then told me that I shouldn't have agreed to move with my sister because she was using me. I had agreed to move with my sister so that she could job shadow a teacher to get her degree.

Up date:

I read the four comments I have so far and thank you guys. I have been thinking back on my time with my ex since we broke up around November of last year and it was the longest relationship I had been in and he still went on the trip, texted me pics of it and then told me how disappointed he was that he couldn't give me a New Years kiss for my birthday. later he also told me the reason he wanted me to go so bad is so we could spend the week doing what he wanted instead of what the family planned.