To my mind your MIL has been abominably rude and your husband insensitive by accepting a gift from anyone with such a provision attached.
So I understand entirely that you are hurt and perhaps feeling resentful right now, although I didn't get any sense of resentment from your post.
In your place, I don't think I would raise the issue with my MIL. It is likely to make bad worse if you do.
You may, on the other hand, feel that in all honesty you have to tell your husband how this made you feel. Whether this is, or is not a good idea, I cannot possibly know, not knowing you or your husband.
I would have been furious with mine for not telling the giver to go and chase herself. But we never had his and her money, only our money. It never mattered who earned most, as long as all the bills were paid.