Jess Mariano is Luke's troubled nephew that comes to live with him during season two of Gilmore Girls. He's played by Milo Ventimigilia and is definitely a love interest and part of a love triangle between Rory and Dean.
Jess: I'm a carnivore.
Emily: Good, I don't see how anybody could resist meat.
Jess: That's why we have teeth.
Emily: That's how I feel.