I just had my interview less than a month ago, and my spouse went with me.
I received two notifications, the first letter was about my naturalization form N-400 and it did not say that my spouse was necessary to be present.
But, the second notification came saying that I was having a combo interview, and the spouse should be present if we were still married or if not, show proof of divorce (the 797 notice had a printed sheet saying about the combo interview, uncomfortable I don't have this document because stayed with the IO, and I was excited about being approved and didn't notice that).
The officer started saying that he was conducting a combo interview, the first was the ROC and my spouse could answer any of his questions, but during the second interview N-400 he should stay quiet and only I could answer.
About documents that he asked for and were not in the letter listing: my spouse's birth certificate and deed/mortgage documents showing that we both owned our home.
IMO: Your wife should go to the interview to support you, is the last phase that you have to do on your immigration process, also as part of the ROC requirement is her be present to them do any questions if necessary. Otherwise, is a red flag to the immigration officer.