I don’t really see how it’s immature to not want to sit home alone while a partner is off doing something fun. If The Bahamas and New Orleans are places you have talked about visiting together, I would be a little annoyed and would try to convince her to pick something else, maybe more in line $-wise with what you’re doing. If NYC is just a weekend thing then I think jetting off to The Bahamas is kind of an overreaction (unless you live in FL). Maybe she can have a weekend with her folks or go to a nearby spa or something. But if this retreat with bro is more along the lines of a week-long trip, fancy hotels, big dinners out, etc. then I definitely think she has a right to do something that week, too. Unfortunately for you, the list of places to go for a weekend and the list of places to go for a week is probably pretty different and the latter may have more places that you both haven’t been and you’ll just have to live with it.
The lucky day off thing just strikes me as her wanting to spend time with you. The buy me dinner part is kind of weird, but I’m also in a 100% shared income marriage so we don’t have to dick around with the whole who buys this and that questions.
The “me too” on buying things also strikes me as an unfortunate result of a split finances situation. If she wants shoes, why doesn’t she just buy them herself? If you control the spending, or insist on running purchases past the other one, and then show up with new kicks, then I can see why she’d be like, hey, I want some new shoes, too.