All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad, sallallaahu`alayhi wa sallam, is His slave and Messenger.
If the matter is as you mentioned that you kindly asked your aunt and your husband’s mother to change the date of the visit, then that is not considered a fault, and she should have understood that and not been angry with you because of it, and your husband should not have resented you for this reason. You can explain the matter to your husband that you wanted the most appropriate time when you would be able to receive her well, and he could explain that to his mother or explain it to her yourself in a good manner. Hopefully she will understand that and the problem will go away, especially since she is your aunt, and aunts are kind and compassionate to their nieces.
And if she has some kind of sensitivity, and she may understand some behaviors wrongly, you should take this into account when dealing with her in the future.
Allah knows best.