This reminds of a joke which I seen b4.. 
the girlfriend got injured and need a blood transfusion, the blood
type is AB+, it is quite rare and the boyfriend happen to be also
AB+, thus the boyfriend agree to transfuse the blood to the
girlfriend.
Not long after, after a heaty arguement, the girlfriend demands a
breakup.
The boyfriend says : "Fine, return the blood that I transfuse to
you"
The girlfriend says : "Fine, I pay with back with monthly
installments."
ROFLMAO!