You don’t let anyone bad mouth him
Sometimes people think they can make a sly remark at your partner’s expense. They misunderstood what kind of partner you are. You don’t take pleasure in teasing your partner behind his back. If someone tries this with you, you lay down the law. You do this even if their criticism of your partner is correct. You’re not going to talk behind your partner’s back, plain and simple. (Okay except with maybe your mom or your best friend).