Anonymous wrote:OP, you can't do it without hurting her feelings. You can be kind about it but there's no way you can set boundaries with your mom that she is going to be happy about. But once you set the boundaries, she will probably learn to live with them and your relationship can improve.
My mom used to complain to me regularly about my father. I finally told her I didn't want to hear it anymore. I could tell she was angry with me but I was tired of this constant pattern of complaining and not doing anything to improve the situation. Finally being able to set boundaries with my mom improved our relationship but no way I could have done it without her being upset about it.
PP is right: there is no way to set boundaries for people who previously didn't have them. Just tell her what you want to tell her. If she asks what color the napkins were, that's probably fine. But if she asks about cousin Janet or uncle George, just tell her to call them up if she wants to know about their experience at the family gathering (in a polite way, of course). That usually keeps the gossip away when I tell people "I don't know, why don't you ask her?"