she's also consider a grandmother. Great-aunt actually
Your great grandfather's sister is your great great aunt. You are her great great niece or great great nephew, depending on your sex.
She will be your aunty
Your grandfather's sister is your great aunt.
Your great grandfather's half-sister is your great great aunt, the same as his full-sister is.
Your grandfather's sister's children are your 'first cousins once removed'.
Two people whose grandfathers were brothers are second cousins to each other.
Your grandfather's great nephew is your second cousin.
She would be your great grandmother
If you have a good relationship with your family members, then nothing is worth breaking that relationship for. She could be jealous of your sister and have possessive tenancies in a relationship. If you are quite early into you relationship with this girl, then you should seriously think about what is important. If you break relations with your family members, then who is going to help pick up the pieces if your relationship doesn't work out. After all you cannot get better support than family.
Your grandfather's cousin is your cousin twice removed. Her husband has no direct relationship to you.
Yes. he has 3 dads and 4 grandfathers
He would be your great-great uncle.