This does not have to “create a permanent wound in the relationship between your husband and your parents”. That would be a choice, and a very unfortunate choice. In the relations between in-laws, there is no better policy than to be eager to overlook slights whenever possible and to be gracious about those that must be addressed directly. If the slights are meant, it foils them. If the slights are not meant, it shows compassion for the clumsiness of them.
You are right, however, that this is a conflict that ought to be handled by the spouse who is the child of the parents, not the in-law. There is nothing wrong with treating it as a conflict, nor anything wrong with the OP telling her parents that she thinks her parents have given the OP and her husband a bait-and-switch. There is nothing wrong with coming out and asking what on earth they can mean by putting such a limitation on a couple that is married in the eyes of the Church. It ought to be done respectfully, it ought to be done with the resolution to really listen with compassion and to try to read between the lines for messages the parents are too embarrassed to voice, but there is nothing wrong with saying, “Mom. Dad. You have to be kidding. We are married…”
Personally, I’d probably live with it for the amount of time it took to find a place of our own, no matter how small and unfurnished it was. I would then kid my parents about the incident mercilessly for the rest of our lives.