Third Wife

Season 1:
Hung Out to Dry (2)
The Curse (5)
My Other Left Foot (12)

In Hung Out To Dry, Ducky first refers to Gibbs having three ex-wives, and that his third wife calls Gibbs every year on the date of their divorce. In The Curse, Ducky mentions that Gibbs' third wife hit Gibbs with a baseball bat and Gibbs required stitches. In My Other Left Foot DiNozzo tells Todd "He (meaning Gibbs) has been married three times..all to redheads."