AITA cutting of sisters

AITA for cutting off my family after finding out my siblings went on vacation together without telling me?
I’m genuinely asking because I want outside opinions—not just people to agree with me.
I have two siblings. I’ve helped both of them out financially in the past. I helped one sibling go to California for a vacation, and I helped the other sibling go to Texas for a vacation. I never expected anything in return for helping them.
Recently, I opened Facebook and discovered that both of them went to Florida together.
The part that hurt wasn’t that they went on vacation. They are adults and can obviously take whatever trips they want. What hurt was finding out through Facebook that they had gone together, while neither one bothered to tell me.
I already have some complicated history with my family, and I’ve felt for a while like I’m the one who gets left out. This just felt like another confirmation that I’m not really considered part of the family unless someone needs something.
So I decided I’m done. I’m cutting off contact with them and stepping away from the family drama.
Now I’m wondering: AITA for cutting my siblings off over this?
I know nobody owes me a vacation invitation, and I’m not saying they weren’t allowed to go. I’m asking whether finding out this way—especially after everything I’ve done to help them—is a reasonable reason to decide I no longer want a relationship with them.
Be honest. AITA?