You could say "No mucho, primo" (Prima for a female cousin)
Your wife's brother is your brother-in-law.
You are not related to your cousin's husband. He would simply be "My cousin's husband."
Your husband's cousin's sister is also your husband's cousin. You are not related to your husband's cousin.
prima = cousin who is a girl primo = cousin who is a boy
De tu primo(a)
hola primo
primo Juan
In genealogy terms she would be "spouse of your first cousin."
Your cousin-in-law.
You could say "¿Conoces a mi primo?"
There are two common ways to say husband in spanish, either esposo or marido.