That's definitely not okay, but before you get angry, try talking to your husband. Maybe there's a reason he didn't say anything then, or maybe he plans on speaking to his cousin in private later. You could possibly ask the cousin why they don't like you and say that you want to understand what you did wrong so that you don't do it again and you can try to get along better. By saying that you want to understand their point of view, you're moving the focus off of them and showing that you are open to beig friends. This makes you the bigger person and is more likely to make the cousin feel guilty about what they have done because they will see that you are really a nice person. Good luck :)