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 Mariano Quotes

Lorelai tries to get Jess to understand that Luke is trying to help him
Jess: What are you sleeping with him or something?
Lorelai: Excuse me?
Jess: I don't know. The whole starry eyed 'you're so much better off, just give it a chance' speech. You're either really nave, or you're getting some.

Jess: Wanna play some poker? Five bucks a hand.
Luke: No.
Jess: Ten? I can't go any higher than ten.
Luke: Jess-
Jess: Okay, fifteen.
Luke: I don't want to play poker.
Jess: You sure?
Luke: Yeah.
Jess: Okie dokie.

Gilmore Girls Quotes

Rory: God! You're like Ruth Gordon just standing there with the tannis root. Make a noise.
Dean: Rosemary's Baby.
Rory: Yeah.
Dean: Well, that's a great movie. You've got good taste. Are you moving?
Rory: No, just my books are.

Emily: I blame Peg Mosley.
Lorelai: Peg Mosley. Evil, evil woman.
Rory: What did Peg Mosley do?
Lorelai: She lured these two German children to her gingerbread house and then she tried to eat them.