I feel like an idiot

I feel so upset and jealous and like a f#* idiot. My SO took his kids on a full week vacation including a cruise to the Caribbean. He is paying for every extra package that he is offered, I think he is going to spend 7k easily.

During the rest of the year he takes them to a different place everyday, takes them on weekend vacations in nature and pays for any special activity the kids want to do.

Every time there’s a special event he makes plans with them and then he asks me if I want to join.

We only went on a long trip 2 years ago that I paid in the most part (hotels and extra expenses) and besides that we have only taken a couple weekend nights away and the rest we spend our time together mostly at home, and we go to a concert every now and then. I pay for a lot more stuff than he does, and when we do something special I try to keep everything low cost.

Going to the beach is what I enjoy most and we never ever go to the beach, and right now he is in the paradise with 2 kids that at 11 and 13 years old are living a life with more luxuries than myself after 20 years working my ass off. He keeps saying things like “it’s a kids cruise” (no, it’s not!), “it’s not my scene”, “there’s too much people”, to try to make me feel better but I know he’s enjoying it very much!

In the meantime I’m taking care of his sick dog, which I happily do, but it’s one more thing I do for him while he does very little for me.

Am I right to feel this is not fair???

EDIT: I wasn’t really invited to this one but I wouldn’t want to go a full week with SKs, I am child free and an introvert and I end exhausted.