You feel that your relation with your husband is good but that may not be the case for him. If he tells that, he is not happy with you that mean he might be having some problem with you. If he tells this openly then his frustration must be high then if he tells on your back. Sit with him and tell him that his attitude is bothering you. Ask him the reasons for his unhappiness with you and try to work out on it. If he disagrees with the fact then discuss about sources from which you got this information. Only open discussion between two of you help you to find out the reasons.