Relationships

[DEMLYND]

In creating our family tree I have uncovered that my father's brother had a relationship with a woman prior to being married and had a daughter. We never knew this and he never had any children with his wife. What official relationship would I be with the daughter, if there was one.

You are your father’s brother’s niece. So his child would be your cousin by blood and not by marriage.

Or to be more exact, you are first cousins to each other.