I’ve talked on occasion about protecting your bride – from your family, from her family, even from your kids if necessary. What’s more, given the emotional differences in men and women, I think it is sometimes good and right to inject yourself into something that does not directly involve you so that you can protect your bride emotionally from another man.
However, there are times when “protecting her” is not the right thing to do. I don’t think it’s a good thing to protect your wife from truth spoken by others, even if that truth is painful or is not expressed in love. This is especially true concerning her interpersonal relationships. If she does things that offend, hurt, or annoy others, telling her she does not do these things, that it’s really them, not her, is not a loving thing to do. Protecting her from the consequences of her actions does not help her, and it may cause others to be hurt if she continues to do those things.
Of course, you risk hearing “whose side are you on?” You can blunt this somewhat by starting with something like “so-and-so was not kind about what she said”, or “he may have had ulterior motives in saying that” but then going on to identify what you see as being true, or at least partly true in what was said. If she knows you are on her side, if she knows you hate to see her hurt, she will learn to trust you when you say, “yeah, that part was valid”.