Your husband and your uncle are not related to each other, although they are both related to you.
Your uncle would call your husband "my niece's husband." Your husband would call your uncle "my wife's uncle."
Aunt
Your husband and your aunt are not related to each other.
You are your aunt's nephew and therefore also her husband's nephew. Her husband is your uncle.
my cousin's husband
Aunt Josephine's husband is Isaac Anwhistle.
Well, isn't that a happy little family tree question! Your aunt's husband's sister is your aunt by marriage. Just think of all the lovely family gatherings and painting sessions you can have together!
You are an aunt/uncle-in-law! Congratulations!! You really are; because you're an aunt/uncle to your niece you are now an aunt/niece by marriage to her husband.
Your mother's sister's husband's sister is your aunt's sister-in-law, but is not related to you. Here's why: Your mother's sister is your aunt. The sister of a woman's husband would be her sister-in-law. In this case the woman is your aunt. So your mother's sister's husband's sister would be your aunt's sister-in-law.
It depends on the actual relationship. It is possible for your aunt's husband's brother to be your father. (She would be an aunt by marriage.) If your aunt is the actual sibling of one of your parents, then, yes, because he is not related to you "by blood ."
Your husband's nephew is also your nephew, and you are his aunt. Remember that if your father has a married brother, the brother is your uncle and the brother's wife is your aunt , with no mention of one being related by marriage and the other not. They are simply your aunt and uncle. The same applies to your relationship to your husband's sibling's children. You are simply their aunt.
You would call your aunt's husband "uncle".
Your mother's sister is your aunt and her husband is your uncle.