"The love of my life"
Guy2: Nahh man. She's a Kelly
If it's a guy? He is F'n hardcore. A "Kelly" will drink your drink, smoke your smoke, eat your philly cheese steak and say, "you got any ranch?" with a smile.
If you have a problem with a "Kelly", you won't realize it till he's gone and you were owned. (see second example)
2. Last night, this Kelly was talkin to my girl. Woke up the next day he's driving my mustang and my bookie sayz I owe him $4600.