Miriam and Aharon approach Moshe and complain that they heard he has separated from his wife. They say that Hashem does not only speak with him and if he separates from his wife, everyone else will as well. Moshe does not respond, rather the passuk in 12:3 tells us that Moshe was the most humble of men.
Passuk 12:3 seems to be out of place. Why is it here that the Torah decides to tell us that Moshe is the humblest of all men?
I think the reason is because the fact that Moshe was the humblest of all men was exactly the answer to Miriam’s issues and therefore it fits exactly. Moshe separated from his wife because Hashem told him to. He had to be ready at every available moment to talk directly with God. Sure, other people were great as well and spoke with God. However, nobody was doing it at the level of Moshe. Hashem even tells Miriam afterwards that they speak directly while everyone else speaks via dreams, etc..
Moshe was the humblest of all men and he therefore was not going to start bragging about how he had to separate from his wife because he speaks directly to God while everyone else only speaks in dreams. Because he was so humble he had no response available. Any response would have made him look haughty.