whenever i make love to my wife (yes, I am loyal

whenever i make love to my wife (yes, I am loyal to her) , and while I'm on top of her (and my dick is inside her sweet and silky vagina) she grasps my buttocks with mer hands and squeeze my cheeks which drive me crazy. but then, she inserts her finger inside my anus! I don't like it when she does this to me, and i told her several times to stop it my anus is mine, it's my private thing, and no one is allowed to tamper with it. but she keeps doing it again and again what to do with this bitch? any help would be appreciated Thank you all