Gaining

Two possible thoughts.

1. You like the contrast of slim and fat. So that when you were slim you prefered fat girls, now you are fat you prefer slim girls.
2. You like the idea of having a very slim girl to fatten up.

I can see the appeal for guys that are really big, having a nice petite girl on his arm.

I however, love the thought of a very large couple walking hand and hand through the shops.

Obvious to all that they share their gluttonous deviation

As for OP's original question.

I was slim and trim and body building, when i met my current partner, and now im aiming for 500lb. But i have always appreciated a nice curvy thin girl with lovely breasts. But ive always said, "they'd be good fun for a night or two, but they could never satisfy me in the long term" like a nice sexy big girl can

Hunter