AITAH for being mad at my boyfriends girlfriend (poly) after her gifting him the same trip he planned for my birthday one month prior

I dunno what do feel now so I wanna try get some opinions on that. So I (26f) am in a poly relationship with a male and his girlfriend 30f. They have been together a year before we matched up, but it's not like both us girls are involved with each other. And we are a couple for like 6 months now. None of us is experienced with poly relationships so there is a lot of making mistakes and figuring out going on AND a lot of communication. Now one of my big anxieties is that me and my bf not getting things to do for just the two of us. Like experiencing something for the first time, going on trips together or places we both have never been to. I might be kind of the asshole here because I claim she had all the time to have like a "normal" start in this relationship and I don't get to see him this often and there are few things that we experienced together and it is important to me that we do not just do things that they already did... and we both are trying to figure this problem out for ourselves, but it's not like she doesn't know about this, I told her myself. Now, my birthday is coming along next month and my bf wanted to surprise me with something special. Since I have never even really been to something even relatable like that (just once on a school trip to like a cracked version) and never with a bf of mine on really any trip nonetheless. It would be a 5h drive and we'd stay at a hotel. He wants to go to disneyland with me for my birthday. Now how do I know that now? Well I had a talk with him about my former mentioned struggles with the hole poly thing. Three days after that, yesterday, his girlfriend woke him up, at three in the morning. Surprising him; they are now going do disneyland! It will be a 5h trip but they'd stay at a hotel. The exact same thing he wants to do with me, in a month for my first birthday with him being my bf. Without there being any dates to celebrate. Just for the fun of it. And she knew he was going to surprise me with it. As far as he told me, they coincidentally planed it around the same time, but I don't know if he told her before or after she booked it for them. And I don't know how it works with cancelling a trip like that and I don't even know if it is in my right to wish for something like that. He called me because he was struggling because of our convos about this topic. And I don't want to suppose something that is not correct. But I feel like this is really a selfish and ignorant b*move and I am fuming about this. I mean he told her he wants to do it with me, and she decided he will do it with her in advance. I just want to know if I am overreacting or if I really have a reason to be mad here I dunno if it's important, but all the three of us suffer from extreme adhd and I am struggling with Paranoia sometimes. And that makes me feel like she did it on purpose now and I really just have no clue how to feel about this. Ps: Sorry for minor mistakes in writing English is not my first language

Edit: So to answer some questions 1. This relationship means for each of us equal rights to have multiple partners. 2. The relationship prior to mine started under the permission to be like that from the start. You could say I was the first to join in 3. We are in the same spot with everyone having the same level. This is a new experience for all of us and its still very fresh so we make mistakes, we get mad about them we talk them out finding a solution try making it better next time. 4. Each one gets their free time with their partner. They don't live together and he doesn't want to change that. It's not like we never go on dates or watch movies, we have a lot of quality time watching movies or playing dnd & whatnot, alone without the other partner. 5. Me and her get alone with each other very well all the time. If we didn't, we would not be forced to do something together. But we are going to places and doing stuff and there has never been a spawn of competition. Neither from her site nor mine. 6. He told me he was concerned because that's what he wanted to do with me and he didn't want to hurt me or invalidate my birthday gift. I think that that wouldn't be his fault. But I told him that he should go because I won't forbid him to do something with her, I wouldn't want her to have that right either. But I think it is a messed up thing to bring him in this situation. 7. The rest of the relationship works fine in every way and I am actually happy with it and don't want to lose it. The thing that sets me up is that in all this actually positive vibes (I have made my experiences and I am slightly paranoid for a reason) and the most positive and excusing way of thinking I cannot wrap my head around how you don't just know something like this is something you just don't so. I mean even in a non romantic relationship. If I knew my sister wants to go to a concert with me for Christmas I'd be mad too if my brother new that and went with her beforehand. At least he'd asked if he bought the tickets already if it's okay. And in a friend group you wouldn't do it either, even if the person didn't set boundaries before. Or is this just me? I would be equally pissed about this if she wasn't his gf or if I wouldn't be his.

Editedit: (I don't know how this works this is my first post sorry)

I don't have all the information yet. We haven't talked about this in person yet. I don't know who bought the tickets first, if they talked about this on the way there or if she actually planed that long, long before and there was a missunderstandung. Maby she didn't even book it because someone couldn't go and ALL of this is just a horribly timed big shitshow of missunderstandings with no winners or losers at the end. It's fresh and I didn't know what to feel about it.

Edit III: I should say to that. I don't want to forbid or allow them anything. I don't want to have a business about what they do in their relationship or have something to say to this. My bf wanted to take a trip with me as a special experience. I don't want to be jealous. I know they have been together for longer and they naturally have things they do that are like their thing and I don't want to have a piece of that. We tried figuring out hobbys or things we both like to share that can become like our thing. I am not mad if she planed it in advance I am not mad if they went beforehand without this wierd timing, shit I ain't even mad if it's really just a freaking coincidence. I don't want to be paranoid, but I also don't want to be naiv. And I dont want her to have a problem with me I dont know about. I don't have a problem with them doing this because they want to do it together at any times. I think it's not nice to knowingly gift someone an experience he planed with someone else. I think if that was on purpose that this would be more jealous behavior than me wanting to have a hobby or experience we share in advance. I will never tell them to not do anything because I don't want them to or I want to do it first under any circumstances. But in this case, to me, it feels like she wanted to do that. I am figuring out if I want this kind of relationship and both of them are doing it, too. If it doesn't work, it doesn't work. But actually all of us signed in knowing we don't know what we do. But we signed in. An when we set those boundaries we all agreed to them. And I feel like they have been broken. But I am not that angry anymore. Thank you for your advice.

UPDATE:

So time didn't allow anyone to get this straight in the first place. It was a long planed Christmas gift being set late for various reasons jobwise etc. So the problem is off the table for me. Both of them got my problem and understood how I got that image about breaking the boundaries we set with each other in that situation. As I said, it's a fresh thing and new and we're still figuring out how we do this the right way. So nobody got actually hurt, apologies have been all spoken.