Is it wrong to discuss about any weird behavior of my in-laws with my husband?

Be totally honest with him. He is your husband, you are as one. You are each others new family now. Letting any other person (including ones mother) intrude in a marriage is only going to cause heartache and trouble! She has no business treating you two like children and you really need to tell your hubby your feelings on that. He should be protective of YOU not them, he has moved on now. Time for him to grow up and act like a man, HE should be telling her that's inappropriate, not you, its his duty to stand up for you on his side. Don't hold it in, you obviously have an issue with it so he is your husband and you need to be totally open and honest about it. Tell him if you feel like he is getting defensive. Find out the real reason why.