Yup, I had a similar problem when I was growing up. My first cousin because my dad and his dad were brothers married my mother’s youngest sister who was my aunt.
[... My first cousin because my dad and his dad were brothers married my mother’s youngest sister who was my aunt....]
BECOUSIN-LAW works for me.
Me too. My maternal grandfather’s sister married my maternal grandmother’s brother.
I never have been able to remember how most of my cousins on that side are related to me and to each other.