Lads holidays

Me and my partner have been together a year and a half. We’ve gone on one holiday in that time and he’s gone on 4 lads holidays. He told me he couldn’t afford another holiday with me so we aren’t doing another one till next year. But now I’ve found out through one of his mates girlfriends that there’s a lads holiday planned for November which is 2.5 weeks in Thailand! I’m fuming, one because he didn’t tell me and two because it’s the 5th lads holiday. Plus Thailand is a big trip and 2.5 weeks is a long time! It’s also something we spoke about doing together so why now doing it with the lads instead?! And if he can’t afford a trip with me how can he afford that one? Honestly it’s becoming an issue and we’ve had multiple conversations about it. How many times do I have to tell him before he listens?! I’ve told him that I’m okay with him going on city break lads holidays for 5-7 days but I’m not okay with a big 2.5 week one in Thailand. I’ve also said I’m okay with him going on lads holiday just not going on this many. It’s the fact that he’s done so many when we’ve not done much, like it’s not fair on me at all. And he always agrees that it’s not fair on me yet does it anyways?! And the last lads holiday he went on, I didn’t hear from him for 23 hours and I found out (from him) the next morning that his mate had bought a girl back to their room, slept with the girl and the girl had stayed the night (in the room they were sharing) to which I flipped and said I was not okay with this happening (they were in twin beds pushed together, therefore in my head she’s slept in bed with my boyfriend). I’m just sick and tired of this childish behaviour from him and him putting his mate first all the time!

Am I being dramatic? Is it outrageous of me to say I’m not okay with him going Thailand and that it could be a deal breaker for us? I just don’t know what to do!