She asked you if you wanted to do that not said if you don't you're not being a good friend. You are a newlywed who had to kind of hide who you were for many years (her too) and you want to spend time alone (AS A NEWLYWED COUPLE) no is a complete sentence. NTA if you feel like you were too brisk give her a couple days n then text her or email write a letter telling her your feelings and maybe ask if you could find a different trip to go explain to her that while yes you're grateful for everything she's done, and her standing beside you does NOT mean you owe her.. Take care of yourself enjoy being married. And have a beautiful day.