my sexual partner
He would be your son's third cousin.
What is your great-great-great grand nephew?!
Your daughter's son's son is your great grandson. Your daughter and your sister's son are first cousins. Your great grandson and your sister's son are first cousins, twice removed. Your great grandson and your sister's great grandchild are third cousins.
My great great second, half, brother in law who's great great grandfathers....son.
Great uncle / Great nephew
Your nephew's grand son is your great great nephew and you are his great great uncle (or aunt)
your son is your great grandsons grandfather.
The son of your great niece is your great great nephew. You are his great great uncle.
cousin
She is your third cousin.
You are your nephew's uncle, or aunt, and his son's great uncle, or great aunt. Your nephew's son is your great nephew.
Your niece's son is your great nephew.He would be your grandnephew